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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Study of scintillation light collection, production and propagation in a 4 tonne dual-phase LArTPC

The 3×1×1 m3 demonstrator is a dual phase liquid argon time projection chamber that has recorded cosmic rays events in 2017 at CERN. The light signal in these detectors is crucial to provide precise timing capabilities. The performance of the photon detection system, composed of five PMTs, are discussed. The collected scintillation and electroluminescence light created by passing particles has been studied in various detector conditions. In particular, the scintillation light production and propagation processes have been analyzed and compared to simulations, improving the understanding of some liquid argon properties.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Quasi-deterministic localization of Er emitters in thin film TiO 2 through submicron-scale crystalline phase control

With their shielded 4f orbitals, rare-earth ions (REIs) offer optical and electron spin transitions with good coherence properties even when embedded in a host crystal matrix, highlighting their utility as promising quantum emitters and memories for quantum information processing. Among REIs, trivalent erbium (Er 3+ ) uniquely has an optical transition in the telecom C-band, ideal for transmission over optical fibers, making it well suited for applications in quantum communication. The deployment of Er 3+ emitters into a thin film TiO 2 platform has been a promising step toward scalable integration; however, like many solid-state systems, the deterministic spatial placement of quantum emitters remains an open challenge. Here, we investigate laser annealing as a means to locally tune the optical resonance of Er 3+ emitters in TiO 2 thin films on Si. Using both nanoscale x-ray diffraction measurements and cryogenic photoluminescence spectroscopy, we show that tightly focused below-gap laser annealing can induce anatase to rutile phase transitions in a nearly diffraction-limited area of the films and improve local crystallinity through grain growth. As a percentage of Er:TiO 2 is converted to rutile, the Er 3+ optical transition blueshifts by 13 nm. We explore the effects of changing laser annealing time and show that the amount of optically active Er:rutile increases linearly with laser power. We additionally demonstrate local phase conversion on microfabricated Si structures, which holds significance for quantum photonics.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Processing and properties of PSZT 95/5 ceramics with varying Ti and Nb substitution

Niobium doped lead-tin-zirconate-titanate ceramics near the PZT 95/5 orthorhombic AFE – rhombohedral FE morphotropic phase boundary Pb 1-0.5y (Zr 0.865-x Ti x Sn 0.135 ) 1-y Nb y O 3 were prepared according to a 2 2+1 factorial design with x = 0.05, 0.07 and y = 0.0155, 0.0195. The ceramics were prepared by a traditional solid-state synthesis route and sintered to near full density at 1250°C for 6 hours. All compositions were ~98% dense with no detectable secondary phases by XRD. The ceramics exhibited equiaxed grains with intergranular porosity and grain size was ~5 μm, decreasing with niobium substitution. Compositions exhibited remnant polarization values of ~32 μC/cm 2 , increasing with Ti substitution. Depolarization by the hydrostatic pressure induced FE-AFE phase transition was drastically affected by variation of the Ti and Nb substitution, increasing at a rate of 113 MPa / 1% Ti and 21 MPa / 1% Nb. Total depolarization output was insensitive to the change in Ti and Nb substitution, ~32.8 μC/cm 2 for the PSZT ceramics. The R3c-R3m and R3m-Pm3m phase transition temperatures on heating ranged from 90 to 105°C and 183 to 191°C, respectively. Ti substitution stabilized the R3c and R3m phases to higher temperatures, while Nb substitution stabilized the Pm3m phase to lower temperatures. Thermal hysteresis of the phase transitions was also observed in the ceramics, with transition temperature on cooling being as much as 10°C lower.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Probing Dynamic Phase Changes in Electrochemical Systems with Cryogenic and in Situ Analytical Electron Microscopy (Final Technical Report)

In this project, we focus on the advancement of our newly developed, unique in situ and cryogenic analytical electron microscopy (AEM) techniques and the development of additional high-end capabilities to quantitatively elucidate the mechanisms of resistive state changes in solid-state electrochemical materials for non-volatile, neuromorphic memory. The objectives of the proposed research are (1) to characterize and elucidate the mechanisms by which electronic state changes occur in various solid-state devices to build guiding principles for electrochemically activated smart materials; (2) to advance our understanding of such mechanisms by coupling cryogenic and in situ techniques to control kinetics of the observed mechanisms while mitigating probe-induced damage; and (3) to utilize additional advanced techniques including electron-beam induced current and quantum mechanical simulations in order to identify the underlying fundamental science of such processes, including roles of defect formation and its effect on phase nucleation, as well as dynamics of these processes in the electrochemical systems at the nanometer scale.

25 ENERGY STORAGE↗
DOE OSTI2021

Evolution of the structure and chemical composition of the interface between multi-component silicate glasses and yttria-stabilized zirconia after 40,000 h exposure in air at 800 °C

The chemical and structural stability of two commercial multicomponent silicate glasses (SCN and G6) in contact with yttria-stabilized zirconia (YSZ) was investigated after exposure times of up to 40,000 h in air at 800 °C. With exposure time, interfacial layers develop at the SCN-YSZ and G6-YSZ interfaces, which were characterized in detail using both quantitative chemical analysis and atomic-resolution imaging. At the SCN-YSZ interface, a Ca-Ba-Si-O reaction phase was found to grow by diffusion control. In G6-YSZ, Raman spectroscopy and electron microscopy revealed a disorganized interfacial reaction later between G6 and YSZ, and the occurrence of cubic to tetragonal to monoclinic phase transformations in YSZ. Finally, this microstructural evolution is discussed in terms of devitrification resistance of glass and diffusion processes at interfaces.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Harvesting Energy from Wastewater by Converting Sewage

This project aims were to develop and demonstrate a scalable, integrated process to convert sewage sludge into renewable natural gas (RNG), enabling wastewater treatment plants (WWTPs) to become net energy producers. The system proposal integrates autothermal hydrothermal liquefaction (AT-HTL), supercritical salt precipitation (SCSP), and hydrothermal gasification (HTG), collectively forming the Supercritical Sludge-to-Gas (SC-S2G) platform. Initially, batch hydrothermal liquefaction reactions were used to screen sewage sludge using AT-HTL (later termed RI-HTL) conversion to biocrude, aqueous and char phases compared to hydrothermal liquefaction (HTL). Significant improvement in biocrude yield using peroxide addition at O:C ratio of 0.05 and under conditions of 300°C for 10 minutes gave 57% biocrude yield and 85% fluid carbon yield (biocrude plus aqueous), while minimizing the loss of carbon to char solids (~7%). Hence, RI-HTL was shown to be effective for conversion of real sewage sludge. The corrosion of the alloy reactor tubes or vessels is an important factor when developing a process that includes an oxidant and a chemically complex feed like sewage sludge. We investigated the corrosion rates on metal alloys at 350°C for 240 hours. Corrosion rates of 0.21 and 0.26 mpy for 304L and 316L stainless steel were measured respectively. The corrosion information obtained in this investigation was utilized by PNNL for design, materials sourcing and construction of the pilot scale continuous flow system.

09 BIOMASS FUELS↗
DOE OSTI2025

Interface morphology and dislocation-mediated processes during rapid solidification of thin films

Rapid solidification experiments have, in recent years, revealed a wealth of new microstructural phenomena that suggest a strong connection between the kinetics of solidification and the crystalline structures that emerge as a result. In this work, we investigate the interplay between interface morphology and defect-mediated processes during rapid solidification conditions using a Phase Field Crystal (PFC) model, enabling us to simultaneously and efficiently explore the physics of solidification and elasto-plasticity in the formalism of a single-field theory. We predict that there are two mechanisms by which dislocations emitted directly from the solid–liquid interface induce orientation gradients as well as the formation of subgrain boundaries within a single solidifying cell. We relate these mechanisms to the morphology of the moving solid–liquid interface and identify a suitable control parameter in the PFC model with which we can go between said morphologies by effectively changing the relative strength of the capillary length and kinetic coefficients of the solid–liquid interface. Thus, we are able to provide mechanistic explanations for several microstructural features (with an emphasis on orientation gradients and subgrain boundaries) observed during the rapid solidification of pure materials. We also provide a simple explanation for the formation of “jagged” subgrain boundaries, which is consistent with our experimental observations in rapidly solidified samples of Aluminum, whose mechanisms have thus far been unknown.

Interface morphology↗
DOE OSTI2023

Integrated Circular Economy Model System for Direct Lithium Extraction: From Minerals to Batteries Utilizing Aluminum Hydroxide

Aluminum hydroxide, an abundant mineral found in nature, exists in four polymorphs: gibbsite, bayerite, nordstrandite, and doyleite. Among these polymorphs gibbsite, bayerite, and commercially synthesized amorphous aluminum hydroxide have been investigated as sorbent materials for lithium extraction from sulfate solutions. The amorphous form of Al(OH) 3 exhibits a reactivity higher than that of the naturally occurring crystalline polymorphs in terms of extracting Li + ions. This study employed high-temperature oxide melt solution calorimetry to explore the energetics of the sorbent polymorphs. The enthalpic stability order was measured to be gibbsite > bayerite > amorphous Al(OH) 3 . The least stable form, amorphous Al(OH) 3 , undergoes a spontaneous reaction with lithium, resulting in the formation of a stable layered double hydroxide phase. Consequently, amorphous Al(OH) 3 shows promise as a sorbent material for selectively extracting lithium from clay mineral leachate solutions. Further, this research demonstrates the selective direct extraction of Li + ions using amorphous aluminum hydroxide through a liquid–solid lithiation reaction, followed by acid-free delithiation and relithiation processes, achieving an extraction efficiency of 86%, and the maximum capacity was 37.86 mg·g –1 in a single step during lithiation. With high selectivity during lithiation and nearly complete recoverability of the sorbent material during delithiation, this method presents a circular economy model. Furthermore, a life cycle analysis was conducted to illustrate the environmental advantages of replacing the conventional soda ash-based precipitation process with this method, along with a simple operational cost analysis to evaluate reagent and fuel expenses.

25 ENERGY STORAGE↗
DOE OSTI2024

Unveiling the effect of Ni on the formation and structure of Earth’s inner core

Ni is the second most abundant element in the Earth’s core. Yet, its effects on the inner core’s structure and formation process are usually disregarded because of its electronic and size similarity with Fe. Using ab initio molecular dynamics simulations, we find that the bcc phase can spontaneously crystallize in liquid Ni at temperatures above Fe’s melting point at inner core pressures. The melting temperature of Ni is shown to be 700 to 800 K higher than that of Fe at 323 to 360 GPa. hcp, bcc, and liquid phase relations differ for Fe and Ni. Ni can be a bcc stabilizer for Fe at high temperatures and inner core pressures. A small amount of Ni can accelerate Fe’s crystallization at core pressures. These results suggest that Ni may substantially impact the structure and formation process of the solid inner core.

58 GEOSCIENCES↗
DOE OSTI2023

A hybrid machine-learning approach for analysis of methane hydrate formation dynamics in porous media with synchrotron CT imaging

Fast multi-phase processes in methane hydrate bearing samples pose a challenge for quantitative micro-computed tomography study and experiment steering due to complex tomographic data analysis involving time-consuming segmentation procedures. This is because of the sample's multi-scale structure, which changes over time, low contrast between solid and fluid materials, and the large amount of data acquired during dynamic processes. Here, a hybrid approach is proposed for the automatic segmentation of tomographic data from time-resolved imaging of methane gas-hydrate formation in sandy granular media, which includes a deep-learning 3D U-Net model. To prepare a training dataset for the 3D U-Net, a technique to automate data labeling based on sample-specific information about the mineral matrix immobility and occasional fluid movement in pores is proposed. Automatic segmentation allowed for studying properties of the hydrate growth in pores, as well as dynamic processes such as incremental flow and redistribution of pore brine. Results of the quantitative analysis showed that for typical gas-hydrate stability parameters (100 bar methane pressure, 7°C temperature) the rate of formation is slow (less than 1% per hour), after which the surface area of contact between brine and gas increases, resulting in faster formation (2.5% per hour). Hydrate growth reaches the saturation point after 11 h of the experiment. Finally, the efficacy of the proposed segmentation scheme in on-the-fly automatic data analysis and experiment steering with zooming to regions of interest is demonstrated.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Evaluations of the Fates of Alkali Metals, Actinides, Mercury, and Iodine During DWPF Recycle Diversion

The fates of alkali metals, actinides, mercury, and iodine in the Defense Waste Processing Facility Recycle Diversion process (as currently conceptualized) have been evaluated through paper studies based on available knowledge of the chemistry, physical properties, solubility, and volatility of the various species involved. The effect of pH in the range from 9 to 13 has been discussed. Recommendations for additional studies to close technology gaps have been provided, many of which are contingent upon the results of pending testing and sample characterization efforts. There is uncertainty in the amounts of soluble actinides passing through the process filter, though the bulk of the actinides should be captured on the filter with the Recycle Collection Tank solids and the total amounts of actinides should be relatively low. The Recycle Collection Tank pH could impact the fraction of actinides reaching the evaporator, but the primary factors determining the actinide fate are expected to be the amount of CO 2 sorption from air sparging or, for certain actinides (such as plutonium), oxidation and/or sorption to MnO 2 solids from permanganate additions to destroy the glycolate anion. Process optimization could minimize the amounts of actinides passing the filter. Depending upon the levels of mercury observed in recycle stream samples and because of the volatility of mercury, the evaporator should be designed with the capability to remove dense mercury phases from the condensate to avoid exceeding ETP WAC limits. The facility design must be adequate to transfer dense mercury phases and testing to confirm mercury transfer is needed. Simulant containing mercury is recommended for both filtration and evaporation testing. OLI Modeling of the various recycle streams is recommended to provide insight on the fate of iodine. Iodine-spiked simulants are recommended for upcoming evaporation tests. The pro) ect should consider the likelihood and impact of NAS scale formation in the evaporators. Process optimization may be needed to minimize the accumulation of NAS scale and possibly the sorption of actinides in the evaporator. Actual waste testing of the Recycle Diversion filtration and evaporation should include the analysis of actinides, mercury, and iodine to determine their partitioning.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2026

Online Alpha Monitoring of High Cs-137 Hanford and SRS High Level Waste with Tensioned Metastable Fluid Detectors

The Department of Energy’s Hanford and Savannah River Sites maintain millions of gallons of caustic supernate and salt high activity waste in their high-level waste (HLW) tank farm inventories. The Savannah River Site is currently treating this waste with a calixarene-based solvent extraction of Cs-137 to reduce these inventories. Hanford is employing an at-tank crystalline silico titanate (CST) based solid phase extraction methodology to reduce their liquid HLW inventories. Due to the high solubility of Cs-137 and the relative insolubility of the actinides in these caustic waste forms, the beta to alpha radioactivity ratio can often exceed six orders of magnitude in the feed solutions to these treatment processes. This unique characteristic leads to significant technical challenges in making rapid gross alpha measurements in the presence of the overwhelming beta, gamma, as well as dissolved sodium salt in these HLW matrices. Conventional radioanalytical techniques, such as liquid scintillation analysis or gas flow proportional counting require significant radiochemistry preparation prior to the radiometric measurements for gross alpha activity. These required pretreatments render these technologies untenable for rapid quantification of gross alpha activity that could be required to support on or at-line measurements ensuring a waste stream will meet regulatory requirements. The radiation measurement properties of Tensioned Metastable Fluid Detectors (TMFDs) have been studied by Purdue University’s Taleyarkhan research group for well over a decade. Fluids tensioned to the appropriate degree will rupture when struck by radiation, resulting in a measurable cavitation event. The negative pressure generating this tension can be adjusted by centrifugal rotation or by acoustic means in such a way that these cavitation events can be generated from alpha radiation but will not be generated by beta or gamma radiation. Purdue University and the Savannah River National Laboratory are currently collaborating to develop a gamma/beta blind, spectroscopic alpha measurement system based on the Tensioned Metastable Fluid Detector technology to provide a potential solution for performing rapid gross alpha measurements on these high gamma/beta sample matrices. Measurements using the Indirect Drive Acoustically Tensioned Metastable Fluid Detectors developed as part of this collaboration were performed with an alpha emitting radionuclide. Successful determination of gross alpha activity was observed, indicating a potential pathway for rapid gross alpha measurements in remote-handled shielded cells or in process situations requiring online alpha monitoring. Measurements using this system have been conducted on high beta activity solutions, demonstrating the beta blind capability of this system. Measurements are currently underway to test the system’s capability to measure gross alpha activity on Savannah River Site high level waste high Cs-137 samples that have been measured by the SRNL radiochemistry team. This work was supported by the DOE EM Technology Development program.

DiPrete, David [Savannah River National Laboratory↗
DOE OSTI2022

Phase Stability of Garnet Solid-Electrolyte Interfacing with Various Cathodes in All Solid-State Batteries

Garnet-structured Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) is one of the most promising electrolyte materials for solid-state Li batteries (SS-LiB). The design and fabrication of a good cathode/electrolyte interface is an important criterion for the SS-LiB. In this work, we performed a systematic study on the impact of cathode crystal structure and chemical compositions on their chemical stabilities against the LLZTO at elevated temperatures, which are required for their adhesion during cell fabrication processes. X-ray Diffraction (XRD) and Rietveld refinement analyses revealed the chemical stabilities of various cathode materials in contact with the LLZTO. While layered LiCoO 2 cathode showed good stability in contact with LLZTO to 900 °C, LiNiO 2 or Ni-rich LiNi x Mn y Co 1–x–y O 2 (NMC) cathodes suffered from the formation of La 4 NiLiO 8 due to La-diffusion from LLZTO. Furthermore, Mn-rich LiMn 2 O 4 spinel and layered LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathodes suffered from the formation of La 2 Zr 2 O 7 due to Li-diffusion and production of Li 2 MnO 3 . As a result, LiNi 0.6 Mn 0.2 Co 0.2 O 2 , having an ideal balance of Ni/Mn/Co composition, or Li 2 MnO 3 containing cathodes such as Li 1.2 Ni 0.15 Mn 0.55 Co 0.1 O 2 were found to have excellent phase stability as the cathodes for LLZTO-based SS-LiBs.

25 ENERGY STORAGE↗
DOE OSTI2023

Plasmon Mediated Near–Field Energy Transfer From Solid–State, Electrically Injected Excitons to Solution Phase Chromophores

An organic diode is demonstrated that near-field energy transfers to molecules in solution via surface plasmon polaritons, in contrast to typical far-field excitation via absorption of traveling photons. Electrically generated excitons couple to surface plasmon modes in the cathode; the plasmons subsequently excite chromophore molecules on top of the cathode. External quantum efficiency and time resolved photoluminescence measurements are used to characterize the diode and the near-field energy transfer process. In addition, it is shown that excited chromophores can charge-transfer to quencher molecules, illustrating the potential of this device to be used for photochemical applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Temporal evolution of Pu and Cs sediment contamination in a seasonally stratified pond

There remains a lack of knowledge regarding ecosystem transfer, transport processes, and mechanisms, which influence the long-term mobility of Pu-239 and Cs-137 in natural environments. Monitoring the distribution and migration of trace radioisotopes as ecosystem tracers has the potential to provide insight into the underlying mechanisms of geochemical cycles. This study investigated the distribution of anthropogenic radionuclides Pu-239 and Cs-137 along with total organic carbon, iron, and trace element in contaminated sediments of Pond B at the Savannah River Site (SRS). Pond B received reactor cooling water from 1961 to 1964, and trace amounts of Pu-239 and Cs-137 during operations. Our study collected sediment cores to determine concentrations of Pu-239, Cs-137, and major and minor elements in solid phase, pore water and an electrochemical method was used on wet cores to determine dissolved elemental concentrations. More than 50 years after deposition, Pu-239 and Cs-137 in sediments are primarily located in the upper 5 cm in area where deposition of particulate-bound contaminants was prevalent and located between 5 and 10 cm in areas of high sedimentation, showing a limited migration of Pu-239 and Cs-137. A Factor analysis demonstrated different sediment facies across the pond resulting in a range of geochemical processes controlling accumulation of Pu and Cs. Highest concentrations appear to be controlled by particulate input from the influent canal, dominated by clay, silt, and sand minerals bearing Fe. Elevated Pu-239 in the sediments were observed in areas with high organic matter and higher deposition rate relative to the Pond B system near the outlet indicating strong association of Pu with OM and particulates. Therefore, organic matter cycling likely plays a role in Pu redistribution between sediment and overlying pond water, and deposition in organic rich sediments accumulating near the outlet. Though Pu appears to have been distributed throughout the pond, Cs-137 concentrations remained the highest near the influent canal.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2020

Structural stability of mechanically alloyed amorphous (FeCoNi) 70 Ti 10 B 20 under high-temperature and high-pressure

Nanostructured (FeCoNi) 70 Ti 10 B 20 (at%) alloy was synthesized by mechanical alloying from elemental powder mixture of Fe, Co, Ni, Ti and B using ball milling. The effect of ball milling time on the evolution of structure and morphology was investigated by X-ray diffraction, scanning and transmission electron microscopy and differential thermal analysis. It was observed that the formation of solid solution of (FeCoNi) 70 Ti 10 B 20 started from the very onset of the milling process. Crystallite size and lattice strains seemed to be leveled off after 20 h of milling with no further major changes. The milling process for longer periods introduced severe plastic deformations causing formation of amorphous phase of (FeCoNi) 70 Ti 10 B 20 . The amorphous alloy composition was confirmed by energy dispersive X-ray spectroscopy analysis that showed an excellent homogeneity of the alloying elements. The phase stability of the mechanically alloyed amorphous sample was further verified by employing high-temperature and high-pressure studies. The alloy samples heat-treated at 700 °C revealed crystallization of the amorphous phase. However, synchrotron-based high-pressure ambient temperature X-ray diffraction studies confirmed that the amorphous phase of the alloy remained stable up to the pressure of 30 GPa. Here, the 50 h milled sample after being annealed at 350 °C showed improvement in the soft magnetic properties of the alloy, which was due to the probable elimination of the residual stress in the amorphous phase of the alloy powders.

36 MATERIALS SCIENCE↗
DOE OSTI2024

A strong fracture-resistant high-entropy alloy with nano-bridged honeycomb microstructure intrinsically toughened by 3D-printing

Strengthening materials via conventional “top-down” processes generally involves restricting dislocation movement by precipitation or grain refinement, which invariably restricts the movement of dislocations away from, or towards, a crack tip, thereby severely compromising their fracture resistance. In the present study, a high-entropy alloy Al0.5CrCoFeNi is produced by the laser powder-bed fusion process, a “bottom-up” additive manufacturing process similar to how nature builds structures, with the microstructure resembling a nano-bridged honeycomb structure consisting of a face-centered cubic (fcc) matrix and an interwoven hexagonal net of an ordered body-centered cubic B2 phase. While the B2 phase, combined with high-dislocation density and solid-solution strengthening, provides strength to the material, the nano-bridges of dislocations connecting the fcc cells, i.e., the channels between the B2 phase on the cell boundaries, provide highways for dislocation movement away from the crack tip. Consequently, the nature-inspired microstructure imparts the material with an excellent combination of strength and toughness.

36 MATERIALS SCIENCE↗