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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 OSTI2018

Effect of Cold Rolling and Heat Treatment on Microstructure and Mechanical Properties of Ti-4Al-1Mn Titanium Alloy

Mechanical behavior of Ti-4Al-1Mn titanium alloy has been studied in annealed, cold-rolled and heat-treated conditions. Room temperature tensile strength as well as % elongation has been found to be low with increasing amount of cold rolling. Lowering of strength in cold worked condition is attributed to premature failure. However, the same has been mitigated after heat treatment. Significant effect of cooling media (air and water) from heat treatment temperature on microstructure was not found except for the degree of fineness of α plates. Optimum properties (strength as well as ductility) were exhibited by samples subjected to 15% cold rolling and heat treatment below β transus temperature, which can be attributed to presence of recrystallized microstructure. In cold worked condition, the microstructure shows fine fragmented α plates/Widmanstätten morphology with high dislocation density along with a large amount of strain fields and twinning, which gets transformed to recrystallized equiaxed microstructure and with plate-like morphology after near β heat treatment. Prior cold work is found to have a significant effect on mechanical properties supported by evolution of microstructure. Twinning is found to be assisting in deformation as well as in recrystallization through the formation of deformation and annealing twins during cold working and heat treatment. Fracture analysis of the tested sample with prior cold work and heat-treated condition revealed quasi-ductile failure as compared to only ductile failure features seen for samples heat treated without prior cold work.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Investigation on Mechanical Properties and Equivalent Model of Aluminum Honeycomb Sandwich Panels

In this study, positive-pressure, bending, and drum peel tests were carried out for aluminum honeycomb sandwich panels made of different materials and with different dimensions. The results of these tests not only precisely revealed the relationships between the mechanical properties of aluminum honeycomb sandwich panels and the material dimensions of the face and core layers, the layout mode of the core layer, and the connecting mode between the face layers and core layers, but also determined the reliable mechanical equivalent model. The test results indicate that when the specimen was subjected to the vertical load, the compression properties of aluminum honeycomb sandwich panels were mainly determined by its core layer, while the face layer mainly relieves the axial stress and restrains the deformation of the core layer. In the flexural test, the face layer is the main part subjected to the load, whereas the core layer shows supporting, stabilizing, and strengthening effects, slowing the deformation of the face layer; flexural-tensile properties can be somewhat affected by the layout type of the core layer. The equivalent plate model, honeycomb plate model, and sandwich panel model were screened based on the experimental results, indicating that the sandwich panel model provided a more accurate description. The sandwich panel model was further modified, ultimately resulting in a more effective equivalent model that can accurately reflect the mechanical properties of the aluminum honeycomb sandwich panels.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Machine learning prediction and experimental verification of Pt-modified nitride catalysts for ethanol reforming with reduced precious metal loading

Ethanol is the smallest molecule containing C–O, C–C, C–H, and O–H bonds present in biomass-derived oxygenates. The development of inexpensive and selective catalysts for ethanol reforming is important towards the renewable generation of hydrogen from biomass. Transition metal nitrides (TMN) are interesting catalyst support materials that can effectively reduce precious metal loading for the catalysis of ethanol and other oxygenates. Herein theoretical and experimental methods were used to probe platinum-modified molybdenum nitride (Pt/Mo 2 N) surfaces for ethanol reforming. Computations using density-functional theory and machine learning predicted monolayer Pt/Mo 2 N to be highly active and selective for ethanol reforming. Temperature-programmed desorption (TPD) experiments verified that ethanol primarily underwent decomposition on Mo 2 N, and the reaction pathway shifted to reforming on Pt/Mo 2 N surfaces. Additionally, high-resolution electron energy loss spectroscopy (HREELS) results further indicated that while Mo2N decomposed the ethoxy intermediate by cleaving C–C, C–O, and C–H bonds, Pt-modification preserved the C–O bond, resulting in ethanol reforming.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

N-3 polyunsaturated fatty acids ameliorate hepatic steatosis via the PPAR-α/CPT-1α pathway in a mouse model of parenteral nutrition

Parenteral nutrition (PN) is one of the basic therapies for patients with intestinal failure; however, hepatic steatosis associated with PN limits the long-term use of PN. N-3 polyunsaturated fatty acids (PUFAs) have been used to improve clinical outcomes of patients receiving PN; however, the mechanisms by which n-3 PUFAs ameliorate hepatic steatosis remain unclear. In the present study, C57BL/6J mice were randomly assigned to three treatment groups, namely, enteral nutrition (EN), n-3 PUFAs, and n-6 PUFAs. Additionally, MK 886 was used to inhibit PPAR-α. After 7 days of intervention, mice were sacrificed, and liver tissue and serum samples were collected. Results from liver weight and liver triglyceride measurements and Oil Red O staining showed that n-3 PUFAs significantly reduced the liver triglyceride levels. In addition, treatment with n-3 PUFAs resulted in a greater decrease in serum triglyceride and low-density lipoprotein cholesterol levels compared to n-6 PUFAs. The key enzymes involved in FA oxidation, namely, PPAR-α and CPT-1α, were significantly restored at both the mRNA and protein levels in the n-3 PUFAs group. However, the benefits of n-3 PUFAs in improving serum and liver TG levels were abolished when the PPAR-α/CPT-1α pathway was blocked by MK 886. The results of this study indicated that n-3 PUFAs ameliorated the PN-associated hepatic steatosis by activating the PPAR-α/CPT-1α pathway. The present study provided a reliable scientific basis supporting the potential benecial effects of n-3 PUFAs for improving hepatic steatosis in patients receiving long-term parenteral nutrition.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

On the competitive antagonism effect in combined chloride-sulfate attack: A numerical exploration

Highlights: • A chemo-physical-mechanical method based on thermodynamic modelling is implemented. • The contradicting findings from reported experiments are numerically explored. • The competitive antagonism effect is time-dependent rather than a conclusive term. • The competitive antagonism effect is quantifiable with a novel assessment criterion. It is of tremendous difficulty to draw a conclusive verdict on the complex process of mutual interference regarding the combined chloride-sulfate attack on concrete, where many have explored the topic, but contradicting results have been reported. In this paper, by taking advantages of the chemo-physical-mechanical method, based on the robust technique of thermodynamic modelling, the competitive antagonism effect in combined chloride-sulfate attack is investigated. Firstly, a range of reported tests are numerically modelled to demonstrate the effectiveness of the employed method in interpreting those opposing and diverse experimental outcomes. More importantly, a fresh conjecture incorporating a novel assessment criterion for the competitive antagonism effect is proposed and supported through a carefully designed illustrative example. Based on the numerical exploration, unique findings and implications for future engineering practices are revealed.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Neural chaos: A spectral stochastic neural operator

Building surrogate models for operators with uncertainty quantification capabilities is essential for many engineering applications where randomness–such as variability in material properties, boundary conditions, and initial conditions–is unavoidable. Polynomial Chaos Expansion (PCE) is widely recognized as a go-to method for constructing stochastic surrogates in both intrusive and non-intrusive ways, and it has recently been used in the context of operator learning. However, its application becomes challenging for complex or high-dimensional processes, as achieving accuracy requires higher-order polynomials, which can increase computational demand and/or the risk of overfitting. Furthermore, PCE requires specialized treatments to manage random variables that are not independent, and these treatments may be problem-dependent or may fail with increasing complexity. Here, in this work, we adopt the same formalism as the spectral expansion used in PCE; however, we replace the classical polynomial basis functions with neural network (NN) basis functions to leverage their expressivity. To achieve this, we propose an algorithm that identifies NN-parameterized basis functions in a purely data-driven manner, without any prior assumptions about the joint distribution of the random variables involved, whether independent or dependent, or about their marginal distributions. The proposed algorithm identifies each NN-parameterized basis function sequentially, ensuring they are orthogonal with respect to the data distribution. The basis functions are constructed directly on the joint stochastic variables without requiring a tensor product structure or assuming independence of the random variables. This approach may offer greater flexibility for complex stochastic models, while simplifying implementation compared to the tensor product structures typically used in PCE to handle random vectors. This is particularly advantageous given the current state of open-source packages, where building and training neural networks can be done with just a few lines of code and extensive community support. We demonstrate the effectiveness of the proposed scheme through several numerical examples of varying complexity and provide comparisons with classical PCE.

Polynomial chaos expansion↗
DOE OSTI2018

In-situ packaging ultra-uniform 3D hematite nanotubes by polyaniline and their improved gas sensing properties

Highlights: • Ultra-uniform 3D α-Fe{sub 2}O{sub 3} nanotubes were packaged by PANI through the two-stage solution processes. • PANI/α-Fe{sub 2}O{sub 3}-based sensor could detect low concentration of acetone (1 ppm) at lower temperature of 180 °C. • The unique structure of α-Fe{sub 2}O{sub 3} support and its synergetic effect with PANI layers improved the sensor performances. - Abstract: This paper reports the PANI (polyaniline)-packaged three-dimensional (3D) α-Fe{sub 2}O{sub 3} nanotubes P/N heterojunction, which was constructed successfully though a facile hydrothermal reaction without adding any surfactant followed by in-situ chemical polymerization in the liquid phase. The structure and morphology of the products were characterized by means of FESEM, XRD, TEM & HRTEM, TGA and FT-IR. Gas sensing test results found that, the PANI/α-Fe{sub 2}O{sub 3} nanocomposite sensor exhibited obviously higher response, lower working temperature (180 °C), fast response and recovery speeds, good selectivity and excellent stability to acetone gas, indicating its promising application for high-performance acetone sensors. The enhanced gas sensing performances can be attributed to the factors like ultra-uniform 3D nanotube-like structure for α-Fe{sub 2}O{sub 3}, the noticeable advantages of PANI, as well as the construction of heterojunction barrier at their interface. The as-prepared PANI/α-Fe{sub 2}O{sub 3} nanocomposite may be also applied in other areas like photocatalysis, water purification, ion batteries, optical devices, and so on.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2026

Adsorption, charge transfer and a coverage-driven transition of alkali metals on rutile TiO 2 (110)

The interaction of alkali metals with metal oxide surfaces is central to tuning surface reactivity in heterogeneous catalysis and photocatalysis. Here we present a comprehensive DFT+U study of the adsorption of alkali metals (Li, Na, K, Rb, Cs) on the (110) surface of rutile TiO 2 . At low coverage (θ = 1/8), all alkali metals bind preferentially to bridging oxygen sites with adsorption energies in the range −4.06 to −3.33 eV, transferring nearly one full electron (0.92–0.99 |e|) to the substrate and inducing Ti 4+ → Ti 3+ reduction. The excess charge localizes preferentially at subsurface Ti sites in the form of small polarons. Diffusion barriers indicate facile motion along bridging-oxygen rows, whereas inter-row hopping is strongly hindered. Coverage effects were examined systematically for potassium: adsorption energy and charge transfer per K atom decrease monotonically with increasing θ. Strikingly, a sharp energy discontinuity occurs between θ = 4/8 and θ = 5/8 (ΔE ≈ 1 eV per atom), which we identify as a coverage-driven structural transition arising from steric packing constraints and enhanced K–K electrostatic repulsion once every (1×1) surface cell is occupied. This structural transition perfectly correlates with a dramatic drop in the work function down to an ultra-low minimum of 0.84 eV at θ=5/8, followed by a metallization- driven recovery at higher coverages. Ab initio molecular dynamics simulations confirm zigzag K arrangements at moderate coverage (θ = 1/3), while at high coverage (θ = 2/3) short-range K–K correlations emerge without long-range order. These results provide atomistic insight into the structure–activity relationships underlying alkali promotion effects on oxide-supported catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Identification of a Unique Inhibitor-Binding Site on Choline Kinase α

Choline kinase α (ChoKα) is an enzyme that is upregulated in many types of cancer and has been shown to be tumorigenic. As such, it makes a promising target for inhibiting tumor growth. Though there have been several inhibitors synthesized for ChoKα, not all of them demonstrate the same efficacy in vivo, though the reasons behind this difference in potency are not clear. One particular inhibitor, designated TCD-717, has recently completed phase I clinical trials. Cell culture and in vitro studies support the powerful inhibitory effect TCD-717 has on ChoKα, but an examination of the inhibitor’s interaction with the ChoKα enzyme has been missing prior to this work. Here we detail the 2.35 Å structure of ChoKα in complex with TCD-717. Examination of this structure in conjunction with kinetic assays reveals that TCD-717 does not bind directly in the choline pocket as do previously characterized ChoKα inhibitors, but rather in a proximal but novel location near the surface of the enzyme. Here, the unique binding site identified for TCD-717 lends insight for the future design of more potent in vivo inhibitors for ChoKα.

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

DNA-PAINT Imaging with Hydrogel Imprinting and Clearing

Hydrogel-embedding is a versatile technique in fluorescence microscopy, offering stabilization, optical clearing, and the physical expansion of biological specimens. DNA-PAINT is a super-resolution microscopy approach based on the diffusion and transient binding of fluorescently labeled oligos, but its feasibility in hydrogels has not yet been explored. In this study, we demonstrate that polyacrylamide hydrogels support sufficient diffusion for effective DNA-PAINT imaging. Using acrydite-anchored oligonucleotides imprinted from patterned DNA origami nanostructures and microtubule filaments in fixed cells, we find that hydrogel embedding preserves docking strand positioning at the nanoscale. Sample clearing via protease treatment had minor structural effects on the microtubule structure and enhanced diffusion and accessibility to hydrogel-imprinted docking strands. Our work demonstrates promising potential for diffusion and binding-based fluorescence imaging applications in hydrogel-embedded samples.

DNA origami↗
DOE OSTI2017

Activation Thermodynamics and H/D Kinetic Isotope Effect of the H ox to H red H + Transition in [FeFe] Hydrogenase

Molecular complexes between CdSe nanocrystals and Clostridium acetobutylicum [FeFe] hydrogenase I (CaI) enabled light-driven control of electron transfer for spectroscopic detection of redox intermediates during catalytic proton reduction. Here in this paper we address the route of electron transfer from CdSe→CaI and activation thermodynamics of the initial step of proton reduction in CaI. The electron paramagnetic spectroscopy of illuminated CdSe:CaI showed how the CaI accessory FeS cluster chain (F-clusters) functions in electron transfer with CdSe. The H ox →H red H + reduction step measured by Fourier-transform infrared spectroscopy showed an enthalpy of activation of 19 kJ mol -1 and a ~2.5-fold kinetic isotope effect. Overall these results support electron injection from CdSe into CaI involving F-clusters, and that the H ox →H red H + step of catalytic proton reduction in CaI proceeds by a proton-dependent process.

09 BIOMASS FUELS↗
DOE OSTI2025

Model-based iterative reconstruction with adaptive regularization for artifact reduction in electron tomography

Obtaining high-quality 3D reconstructions from electron tomography of crystalline particles embedded in lighter support elements is crucial for various material systems such as catalysts for fuel cell applications. However, significant challenges arise due to the limited tilt range, sparse and low signal-to-noise ratio of the measurements. In addition, small metal particles can cause strong streaking and shading artifacts in the 3D reconstructions when using conventional reconstruction algorithms due to the presence of Bragg diffraction and the large scattering cross-section difference between the materials of the particles and the background support regions. These artifacts lead to errors in the downstream characterization affecting extraction of critical features such as the size of the metal particles, their distribution and the volume of the lighter support regions. In this paper, we present a two-stage algorithm based on metal artifact reduction, utilizing model-based iterative reconstruction methods with adaptive adjustment of regularization parameters. Our approach yields high-quality 3D reconstructions compared to traditional algorithms, accurately capturing both the metal particles as well as the background support. We demonstrate the effectiveness of our algorithm through simulated and experimental bright-field electron tomography data, showing significant improvements in reconstruction quality compared to traditional methods.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Equity and modeling in sustainability science: Examples and opportunities throughout the process

Equity is core to sustainability, but current interventions to enhance sustainability often fall short in adequately addressing this linkage. Models are important tools for informing action, and their development and use present opportunities to center equity in process and outcomes. This Perspective highlights progress in integrating equity into systems modeling in sustainability science, as well as key challenges, tensions, and future directions. We present a conceptual framework for equity in systems modeling, focused on its distributional, procedural, and recognitional dimensions. We discuss examples of how modelers engage with these different dimensions throughout the modeling process and from across a range of modeling approaches and topics, including water resources, energy systems, air quality, and conservation. Synthesizing across these examples, we identify significant advances in enhancing procedural and recognitional equity by reframing models as tools to explore pluralism in worldviews and knowledge systems; enabling models to better represent distributional inequity through new computational techniques and data sources; investigating the dynamics that can drive inequities by linking different modeling approaches; and developing more nuanced metrics for assessing equity outcomes. We also identify important future directions, such as an increased focus on using models to identify pathways to transform underlying conditions that lead to inequities and move toward desired futures. By looking at examples across the diverse fields within sustainability science, we argue that there are valuable opportunities for mutual learning on how to use models more effectively as tools to support sustainable and equitable futures.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Analysis of AP1000 Small-Break Loss-of-Coolant Accident Using Reactor Transient Simulator

The Westinghouse Electric Company’s Advanced Passive Reactor (AP1000) is characterized by the incorporation of passive safety systems (PSSs) designed to ensure core cooling during transient events. The assessment of PSSs requires evaluation of their performance through a combination of experiments and simulations employing various thermal-hydraulic codes. In addition, detailed evaluation of PSSs for a specific reactor system transient analysis such as loss-of-coolant-accident analysis supports understanding representative integral effects test facility development and the further evolution model development and assessment process. Developing a reactor system code is a complex and time-consuming process that requires significant engineering expertise and effort. It can take several months to even years to complete in the early stages of reactor system design and analysis. However, this process can be expedited through the use of transient simulator models for similar reactor systems, which can be used for lesson learning and training purposes. This study uses the Personal Computer Transient Analyzer (PCTRAN) code. The main advantage of PCTRAN is its ease of use and ability to run faster than real time. This study presents the results obtained for a small-break loss-of-coolant accident (SBLOCA) for two breaks using the full version (licensed) of PCTRAN. The purpose of this investigation is to evaluate the overall system behavior during the postulated SBLOCA event as well as assess the capability of the PCTRAN code to reproduce the system response during transient events. The obtained results were compared with the Westinghouse NOTRUMP system code. The PCTRAN code proved to be reliable in predicting the qualitative behavior of the system in both transient cases. As for the system response, it was found that it is contingent on the activation time of the PSSs. The differences in reactor coolant system pressure between the two codes were attributed to the critical flow model and simplification of mass and energy balance. Despite PCTRAN’s limitations, it can still provide a reasonable prediction of various reactor parameters such as pressure, mass flow rate, and void fraction during a SBLOCA scenario. It is worth noting that PCTRAN currently employs a bulk approach similar to that of the Modular Accident Analysis Program (MAAP) and MELCOR codes. However, the upcoming version of PCTRAN will include an artificial intelligence–based detection and accident prevention system, as well as different models for different reactor components. Consequently, PCTRAN has the potential to be upgraded to match the system thermal-hydraulic codes of the U.S. Nuclear Regulatory Commission and become more widely used in cybersecurity to safeguard nuclear power plants from cyberattacks.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2019

Peroxisomal Fatty Acid β-oxidation negatively impacts plant survival under salt stress

Peroxisomal β-oxidation is the sole pathway for metabolic breakdown of fatty acids to generate energy and carbon skeletons in plants, is essential for oilseed germination and plays an important role in growth, development and cellular homeostasis. Yet, this process also produces cytotoxic reactive oxygen species (ROS) as byproducts. We recently showed that disruption of fatty acid β-oxidation enhance plant survival under carbon starvation conditions. Here, we extend these findings by demonstrating that blocking fatty acid import into peroxisomes reduces ROS accumulation and increases plant tolerance to salt stress, whereas increasing fatty acid flux into the β-oxidation pathway has opposite effects. Together, these results support the view that peroxisomal β-oxidation of fatty acids enhances stress-induced ROS production, thereby negatively impacting plant survival under adverse environmental conditions.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Integrated modeling of alpha particle losses in JET DT plasmas

Alpha particle confinement is crucial for sustaining burning plasmas and designing future reactor concepts. Along with classical/prompt losses, various magnetohydrodynamic instabilities can lead to wave-particle interactions which can transport alpha particles outward from the plasma. This can result in a reduction in plasma heating/performance, and, at worst, damage in-vessel components. Joint European Torus’s recent deuterium–tritium campaigns in 2021–2023 have produced numerous alpha particle loss measurements with its scintillator probe and Faraday cup array fast ion loss detectors as discussed in Bonofiglo et al (2024 Nucl. Fusion 64 096038). This paper will report on integrated energetic particle transport modeling in support of those measurements. The modeling is accomplished with the TRANSP and ORBIT-kick codes with the use of recently developed reduced models which calculate mode structure, amplitude, and the evolving dynamics. When possible, constraints and comparisons to experiment are conducted. Case studies are performed on a variety of magnetohydrodynamic activity, including: fishbones, tearing modes (TMs), and sawtooth crashes. Additionally, a special case of an alpha-driven toroidal Alfvén eigenmode is briefly discussed, where modeling showed marginally weak alpha losses and was unable to support experimental observations. Coupled effects between a TM and toroidal field ripple are presented and were unable to replicate the observations in lost particle pitch but did duplicate the localized flattening of the measured neutron profile. Additional modeling results compare the magnitude of losses and energy/velocity-space sensitivities against experimental observations/measurements for each scenario. This work corroborates numeric alpha transport modeling while also identifying model deficiencies. While this report details alpha transport, it also presents open issues for discussion in assessing the validity of our numerical models towards burning plasmas.

Bonofiglo, Phillip J. [Princeton Plasma Physics La↗