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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 1,387 records · Page 77
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on PmAu3 by Materials Project

PmAu3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pm3+ is bonded in a distorted body-centered cubic geometry to fourteen Au1- atoms. There are eight shorter (3.05 Å) and six longer (3.52 Å) Pm–Au bond lengths. There are two inequivalent Au1- sites. In the first Au1- site, Au1- is bonded to four equivalent Pm3+ and four equivalent Au1- atoms to form a mixture of distorted face, edge, and corner-sharing AuPm4Au4 tetrahedra. All Au–Au bond lengths are 3.05 Å. In the second Au1- site, Au1- is bonded in a 8-coordinate geometry to six equivalent Pm3+ and eight equivalent Au1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Power Generation Cycle with RELAP-7

Balance of plant of a High-Temperature gas-cooled Reactor – Pebble bed Module (HTR-PM) is modeled using RELAP-7. The model includes the primary helium loop where the heat produced by the core is transferred to a helical-coil steam generator and the secondary loop where super-heated steam is fed to a turbine to extract power. The steam is then condensed to subcooled water and pumped back into the steam generator. Results demonstrate that RELAP-7 has the capability to model different regimes encountered in two-phase flow with wall boiling, superheated steam, subcooled liquid and condensation. RELAP-7 also has the capability of modeling different fluids with their own specific models in a very flexible way, without any code change. This also demonstrates the capability of modeling the transfer of fission power into electrical power.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

Investigation of Lubricant Additive Interactions on Gasoline Particulate Filters

To understand how the composition of novel lubricant additives and their ash interact with gasoline particulate filters (GPFs), an accelerated aging protocol was conducted using three lubricant additive formulations and two GPF types. The additive packages (adpaks) consisted of Ca+Mg detergent in a 3:1 or 0:1 ratio and an anti-wear component—either zinc dialkyl dithiophosphate (ZDDP) or a novel phosphonium-phosphinate ionic liquid (IL) substitute. The particulate sampling captured amount/compositions of particulate matter (PM) generated, total particulate number, and size distribution. Five ash loadings were completed. GPF position and adpak composition affected the backpressure, ash composition, ash morphology, and captured mass. The particulate sampling indicated that the ash component consisted primarily of particles less than 50 nm in size and that the Mg-only adpak resulted in more particulate of 50–400 nm in size. Postmortem materials characterization indicated GPFs in the underfloor position had deeper penetration of ash into the walls compared to the close-coupled position. Additionally, the Mg-only adpak had a higher filter collection efficiency (>90%) and the ash particles consisted of a higher concentration of dense ash material. In contrast, four of the 3:1 Ca:Mg lubricant adpaks resulted in a collection efficiency of only 40–50%. Although the collection efficiency was higher with the Mg-only adpak, the ash layer in the GPF was not thicker, nor was the penetration into the wall more significant, and surprisingly the full useful life (FUL) backpressure was lower than with Ca:Mg adpaks. The higher density of the Mg-derived ash was the only detectable difference. A possible explanation of this observation is that Mg ash has a lower melting point and is more susceptible to densification during combustion or GPF regeneration. The substitution of IL in place of the ZDDP did not lead to any notable changes in collection efficiency or location of the ash.

42 ENGINEERING↗
DOE OSTI2022

Initial study on cross section generation requirements for a PBR equilibrium core

A Serpent model of the HTR-PM equilibrium core was developed for use in cross section prepa-ration studies in order to guide methods development for the Griffin reactor multiphysics applica-tion. The model includes detailed isotopics for 10 distinct pebble burnup groups in 126 core zoneswith unique fuel and moderator temperatures obtained from a coupled neutronics-thermal-fluidsequilibrium core calculation using Griffin-Pronghorn. A sensitivity study of the fuel and mod-erator temperatures for various core regions was performed with the MOOSE stochastic tools.The results show that the uncertainties are, not unexpectedly, dominated by the value of the fluidtemperature and that the power level, heat transfer coefficient and effective conduction to neigh-boring pebbles and fluid constitute, at best, second order effects. The temperature uncertaintyrange varies from 28 K to 57 K at the core entry and exit planes, respectively, but these val-ues are probably higher. We still have to quantify the significance of these uncertainties in thepreparation of cross sections, which will be postponed for future work. In addition, we verifythat the single effective pebble approach works well for the preparation of region averaged crosssections in the infinite domain approximation. Nevertheless, there are significant discrepanciesin the cross sections when compared to the multi-pebble model. This could affect the predictionof peak values and in the depletion calculation. We conclude that is highly desirable for futurestudies with Griffin to be able to handle both the ?effective? pebble approximation and the multi-pebble approach for the various pebble burnup groups. This enables Griffin users the flexibilityto perform higher-fidelity studies. Finally, we initiate the preparation of cross sections for variouscore regions from the full core Serpent reference model. We quantify the differences in 26 groupcross sections from infinite domain models. These reference cross sections will serve to validatethe double heterogeneity, self-shielding, and spectrum-correction methods in Griffin.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Powder Metallurgy – Hot Isostatic Pressing of 316H Stainless Steel for Nuclear Components

Overview of the PM-HIP work performed on stainless steel 316H as part of the microreactor program. High temperature mechanical testing was performed, with concerns identified with the creep-fatigue performance. Variations in feedstock and processing parameters did not conclusively identify the primary factor in the reduced creep-fatigue performance.

36 - MATERIALS SCIENCE↗
DOE OSTI2025

Universal Electronic‐Structure Relationship Governing Intrinsic Magnetic Properties in Permanent Magnets

An electronic-structure-centered perspective is presented on permanent-magnet (PM) design, highlighting two key levers, that is, saturation magnetization (M s ), governed by 3d-band filling and exchange physics, and magnetocrystalline anisotropy energy (MAE), arising from spin-orbit coupling (SOC) on anisotropic orbital populations. Reviewing current practices, including DFT-based MAE/J ij extraction, atomistic-spin and micromagnetic modeling, and high-throughput machine learning (ML) pipelines, three bottlenecks limiting predictive discovery is identified that is i) electronic-structure accuracy for small MAE (sensitive to functional choice, Hubbard U, and many-body effects), ii) finite-temperature and kinetic realism (phonon/magnon renormalization, ordering kinetics), and iii) descriptor and multiscale decoupling (lack of SOC-weighted and orbital-resolved fingerprints). Deep dives into the electronic-structure of Nd─Fe─B and Fe─N show how these fingerprints govern magnetic performance, motivating DFT- and quantum-mechanics-based descriptors for discovery. Unbiased, structure-driven exploration, coupled with high-throughput simulations, ML, generative AI, and reasoning models, accelerates candidate identification and propagates insights across scales. Addressing supply-chain risks, on future needs of designing “critical-element-free” magnets with tailored microstructure and high energy products is emphasized. By integrating electronic fingerprints, AI reasoning, and multiscale modeling, a practical roadmap is provided for rare-earth-lean or rare-earth free, high-performance, sustainable PMs.

Singh, Prashant [Ames Laboratory, and Iowa State U↗
DOE OSTI2020

2D Electrets of Ultrathin MoO 2 with Apparent Piezoelectricity

Since graphene, a variety of 2D materials have been fabricated in a quest for a tantalizing combination of properties and desired physiochemical behavior. 2D materials that are piezoelectric, i.e., that allow for a facile conversion of electrical energy into mechanical and vice versa, offer applications for sensors, actuators, energy harvesting, stretchable and flexible electronics, and energy storage, among others. Unfortunately, materials must satisfy stringent symmetry requirements to be classified as piezoelectric. Here, 2D ultrathin single-crystal molybdenum oxide (MoO 2 ) flakes that exhibit unexpected piezoelectric-like response are fabricated, as MoO 2 is centrosymmetric and should not exhibit intrinsic piezoelectricity. However, it is demonstrated that the apparent piezoelectricity in 2D MoO 2 emerges from an electret-like behavior induced by the trapping and stabilization of charges around defects in the material. Arguably, the material represents the first 2D electret material and suggests a route to artificially engineer piezoelectricity in 2D crystals. Specifically, it is found that the maximum out-of-plane piezoresponse is 0.56 pm V -1 , which is as strong as that observed in conventional 2D piezoelectric materials. The charges are found to be highly stable at room temperature with a trapping energy barrier of ≈2 eV.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Unlocking Electrostrain in Plastically Deformed Barium Titanate

Achieving substantial electrostrain alongside a large effective piezoelectric strain coefficient (d 33 *) in piezoelectric materials remains a formidable challenge for advanced actuator applications. Here, in this work, a straightforward approach to enhance these properties by strategically designing the domain structure and controlling the domain switching through the introduction of arrays of ordered {100}<100> dislocations is proposed. This dislocation engineering yields an intrinsic lock-in steady–state electrostrain of 0.69% at a low field of 10 kV cm -1 without external stress and an output strain energy density of 5.24 J cm -3 in single-crystal BaTiO 3 , outperforming the benchmark piezoceramics and relaxor ferroelectric single-crystals. Additionally, applying a compression stress of 6 MPa fully unlocks electrostrains exceeding 1%, yielding a remarkable d 33 * value over 10 000 pm V -1 and achieving a record-high strain energy density of 11.67 J cm -3 . Optical and transmission electron microscopy, paired with laboratory and synchrotron X-ray diffraction, is employed to rationalize the observed electrostrain. Phase-field simulations further elucidate the impact of charged dislocations on domain nucleation and domain switching. These findings present an effective and sustainable strategy for developing high-performance, lead-free piezoelectric materials without the need for additional chemical elements, offering immense potential for actuator technologies.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Direct Evidence of Graphene-Induced Molecular Reorientation in Polymer Films

For the first time, direct evidence of graphene-induced molecular reorientation in polymer films using polarization modulated infrared reflection absorption spectroscopy (PMIRRAS) are presented. By creating favorable electrostatic interactions, graphene-polymer interfaces can be controlled by varying polymer and solvent composition. After trans of unmodified graphene from copper onto a polymer substrate, polymer chain rearrangement relative to the orientation at the polymer-copper interface is observed using PM-IRRAS. Transfer success is characterized using both optical transmission measurements and Raman spectroscopy to quantify the transfer fidelity, i.e. graphene coverage fraction. Taken together, oxygencontaining poly(ethylene-co-vinyl acetate) shows more polymer chain rearrangement and better graphene coverage compared to oxygen-free polyethylene. Polymer composition seems to dominate graphene-polymer interactions while solvent choice has a smaller effect on transfer quality. These results are the first direct measurement of this effect and point towards the possibility of engineering graphene-polymer interactions for specific applications.

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

Large Non‐Resonant Infrared Optical Second Harmonic Generation in Bulk Crystals of Van der Waals Semiconductor, SnP 2 Se 6

2D van der Waals (vdW) materials have emerged as a highly promising candidates for nonlinear optical (NLO) applications. This study presents the synthesis, comprehensive linear optical, and optical second harmonic generation (SHG) characterization of a novel 2D vdW semiconductor SnP2Se6 in its bulk single crystal form. It exhibits an indirect bandgap of ≈1.47 eV and an exceptional non-resonant SHG coefficient of d 33 ∼ −222 ± 30 pm V −1 at a fundamental wavelength of 2 µm, which is ≈7 times larger than that of the commercial AgGaSe 2 with a comparable bandgap. Density functional theory (DFT) calculations of the linear and nonlinear optical properties exhibit reasonable agreement with the experimental measurements, revealing the chemical origin of the enhanced properties. Moreover, SnP 2 Se 6 can exhibit both type-I and type-II phase matching over a wide spectral range, fulfilling one of the key criteria for an ideal NLO crystal. These exceptional properties position SnP 2 Se 6 as a highly promising candidate for NLO applications.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Molecularly Imprinted Polymer Sensor Empowered by Bound States in the Continuum for Selective Trace-Detection of TGF-beta

The integration of advanced materials and photonic nanostructures can lead to enhanced biodetection capabilities, crucial in clinical scenarios and point-of-care diagnostics, where simplified strategies are essential. Herein, a molecularly imprinted polymer (MIP) photonic nanostructure is demonstrated, which selectively binding to transforming growth factor-beta (TGF-β), in which the sensing transduction is enhanced by bound states in the continuum (BICs). The MIP operating as a synthetic antibody matrix and coupled with BIC resonance, enhances the optical response to TGF-β at imprinted sites, leading to an augmented detection capability, thoroughly evaluated through spectral shift and optical lever analogue readout. The validation underscores the MIP-BIC sensor capability to detect TGF-β in spiked saliva, achieving a limit of detection of 10 fM and a resolution of 0.5 pM at physiological concentrations, with a precision of two orders of magnitude above discrimination threshold in patients. The MIP tailored selectivity is highlighted by an imprinting factor of 52, showcasing the sensor resistance to interference from other analytes. The MIP-BIC sensor architecture streamlines the detection process eliminating the need for complex sandwich immunoassays and demonstrates the potential for high-precision quantification. This positions the system as a robust tool for biomarker detection, especially in real-world diagnostic scenarios.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2025

Realization of Non‐Equilibrium Wurtzite Structure in Heterovalent Ternary MgSiN 2 Film Grown by Reactive Sputtering

The piezoelectric and ferroelectric applications of heterovalent ternary materials are not well explored. Epitaxial MgSiN 2 films are grown at 600 °C on (111)Pt//(001)Al 2 O 3 substrates by the reactive sputtering method using metallic Mg and Si under the N 2 atmosphere. Detailed X-ray diffraction measurements and transmission electron microscopy observations revealed that the epitaxially grown films on the substrates have a hexagonal wurtzite structure with c-axis out-of-plane orientation. The random occupation of this structure by Mg and Si differs from that of the previously reported structure in which these two cations periodically occupy the cationic sites. However, the lattice spacings closely approximate those that are previously reported, irrespective of the ordering, and they are almost comparable with those of (Al 0.8 Sc 0.2 )N. The wide bandgap of >5.0 eV in deposited MgSiN 2 is compatible with that of AlN and suggests durability against the application of strong external electric fields, possibly to induce polarization switching. In addition, MgSiN 2 is shown to have piezoelectric properties with an effective d 33 value of 2.3 pm V −1 for the first time. This work demonstrates the compositional expansion of hexagonal wurtzite to heterovalent ternary nitrides for novel piezoelectric materials, whose ferroelectricity is expected.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Processing and properties of hafnium-doped tin-modified lead zirconate titanate 95/5 ceramics

Niobium (Nb)-doped lead-tin-zirconate-titanate (PSZT) ceramics near the lead-zirconate-titanate 95/5 orthorhombic AFE-rhombohedral FE morphotropic phase boundary (PSZT 13.5/81/5.5 -1.6Nb) were prepared with up to 10 mol.% of hafnium (Hf) substituted for zirconium. The ceramics were prepared by a traditional solid-state synthesis route and sintered to near full density at 1150°C for 6 h in sealed alumina crucibles with self-same material as the lead vapor source. All compositions were ~98% dense with no detectable secondary phases by X-ray diffraction. The grain size was ~3 μm for all compositions, consisting of equiaxed grains with intergranular porosity. The compositions exhibited remnant polarization values of ~32 μC/cm 2 . Depolarization by the hydrostatic pressure-induced FE-AFE phase transition occurred at 310 MPa for all compositions, resulting in a total depolarization output of 32.4 μC/cm 2 for the PSZT ceramics. Evaluation of the R3c-R3m and R3m-Pm $\bar{3}$ m phase transition temperatures by impedance spectroscopy showed temperatures on heating ranging from 86 to 92°C and 186 to 182°C, respectively, for increasing nominal Hf content. Thermal hysteresis of the phase transitions was also observed in the ceramics, with the transition temperature on cooling being 1–4°C lower. The study demonstrated that the PSZT ceramics are relatively insensitive to variations in Hf content in the range of 0 to 10 mol.%.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Combining the Best of Two Chelating Titans: A Hydroxypyridinone-Decorated Macrocyclic Ligand for Efficient and Concomitant Complexation and Sensitized Luminescence of f-Elements

An ideal chelator for f-elements features rapid kinetics of complexation, high thermodynamic stability, and slow kinetics of dissociation. Here we present the facile synthesis of a macrocyclic ligand bearing four 1-hydroxy-2-pyridinone units linked to a cyclen scaffold that rapidly forms thermodynamically stable complexes with lanthanides (Sm 3+ , Eu 3+ , Tb 3+ , Dy 3+ ) and a representative late actinide (Cm 3+ ) in aqueous media and concurrently sensitizes them. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed an increase in the Ln/An-O bond lengths following the trend Cm>Eu>Tb and EXAFS data were compatible with time-resolved luminescence studies, which indicated one to two water molecules in the inner metal coordination sphere of Eu(III) and two water molecules for the Cm(III) complex. Spectrofluorimetric ligand competition titrations against DTPA confirmed the high thermodynamic stability of DOTHOPO complexes, with pM values between 19.9(1) and 21.9(2).

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

Giant Dipole Moments: Remarkable Effects Mono‐, Di‐, and Tri‐ Hydrated 5,6‐Diaminobenzene‐1,2,3,4‐Tetracarbonnitrile

The molecule 5,6-diaminobenzene-1,2,3,4-tetracarbonnitrile (MOI) was first synthesized by Müllen and coworkers in 2016 and boasts an ultrastrong dipole moment of $14.1\pm 0.7$ Debye in THF. Gas phase DFT computations do not fully reflect this ultrastrong dipole moment, demonstrating the role of solvent in increasing this dipole moment. Here, we investigate the effect of solvent molecule position on the dipole moment of this species, computationally examining systems with giant dipole moments. These systems are optimized in the gas phase with the B3LYP functional, employing the aug-cc-pVTZ and def2-TZVP basis sets, as well as the B3LYP-D3BJ/aug-cc-pVTZ functional in Orca. Single point DLPNO-CCSD/aug-cc-pVDZ results were obtained from Orca and Psi4, as well as DLPNO-CCSD(T)/CBS information from Psi4. Additionally, these are compared to the dipole moments of di- and tri-hydrated systems, and the SMD models for THF and water at the B3LYP/aug-cc-pVTZ level of theory. The dissociation energies, HOMO-LUMO energy gaps, and dipole moments are presented. These metrics show the nh1nh1′ THF system boasts the largest dissociation energy and dipole moment of the singly solvated systems, due to its strong hydrogen bonding. The importance of solvent placement is highlighted and may guide the synthesis of macromolecules or organic frameworks incorporating the MOI or MOI-like subunits. Remarkably, a single solvent molecule provides a good model for the difference between the gas phase and solvated species. The predicted gas phase dipole moments computed with B3LYP/aug-cc-pVTZ for the MOI, its monohydrated complex, dihydrated complex, and its trihydrated complex are 9.6, 14.2, 16.0, and 16.8 Debye, respectively.

dipole↗
DOE OSTI2020

Detection of a multi–disease biomarker in saliva with graphene field effect transistors

Human carbonic anhydrase 1 (CA1) has been suggested as a biomarker for identification of several diseases including cancers, pancreatitis, diabetes, and Sjogren’s syndrome. However, the lack of a rapid, cheap, accurate, and easy-to-use quantification technique has prevented widespread utilization of CA1 for practical clinical applications. To this end, we present a label-free electronic biosensor for detection of CA1 utilizing highly sensitive graphene field effect transistors (G-FETs) as a transducer and specific RNA aptamers as a probe. The binding of CA1 with aptamers resulted in a positive shift in Dirac voltage V D of the G-FETs, the magnitude of which depended on target concentration. These aptameric G-FET biosensors showed the binding affinity (K D ) of ~2.3 ng/ml (70 pM), which is four orders lower than that reported using a gel shift assay. This lower value of K D enabled us to achieve a detection range (10 pg/ml - 100 ng/ml) which is well in line with the clinically relevant range. These highly sensitive devices allowed us to further prove their clinical relevance by successfully detecting the presence of CA1 in human saliva samples. In conclusion, the utilization of this label-free biosensor could facilitate the early stage identification of various diseases associated with changes in concentration of CAs.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2021

Interferometric 4D-STEM for Lattice Distortion and Interlayer Spacing Measurements of Bilayer and Trilayer 2D Materials

Van der Waals materials composed of stacks of individual atomic layers have attracted considerable attention due to their exotic electronic properties that can be altered by, e.g., manipulating the twist angle of bilayer materials or the stacking sequence of trilayer materials. To fully understand and control the unique properties of these few-layer materials, a technique that can provide information about their local in-plane structural deformations, twist direction, and out-of-plane structure is needed. In principle, interference in overlap regions of Bragg disks originating from separate layers of a material encodes 3D information about the relative positions of atoms in the corresponding layers. Here, an interferometric 4D scanning transmission electron microscopy technique is described that utilizes this phenomenon to extract precise structural information from few-layer materials with nm-scale resolution. It is demonstrated how this technique enables measurement of local pm-scale in-plane lattice distortions as well as twist direction and average interlayer spacings in bilayer and trilayer graphene, and therefore provides a means to better understand the interplay between electronic properties and precise structural arrangements of few-layer 2D materials.

36 MATERIALS SCIENCE↗