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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Emergence of shallow energy levels in B-doped Q-carbon: A high-temperature superconductor

We report the spectroscopic demonstration of the shallow-level energy states in the recently discovered B-doped Q-carbon Bardeen-Cooper-Schrieffer (BCS) high-temperature superconductor. The Q-carbon is synthesized by ultrafast melting and quenching, allowing for high B-doping concentrations which increase the superconducting transition temperature (Tc) to 36 K (compared to 4 K for B-doped diamond). The increase in Tc is attributed to the increased density of energy states near the Fermi level in B-doped Q-carbon, which give rise to superconducting states via strong electron-phonon coupling below Tc. These shallow-level energy states, however, are challenging to map due to limited spatial and energy resolution. Here, we use ultrahigh energy resolution monochromated electron energy-loss spectroscopy (EELS), to detect and visualize the newly formed shallow-level energy states (vibrational modes) near the Fermi level (ranging 30–100 meV) of the B-doped Q-carbon. In this work, we establish the significance of high-resolution EELS in understanding the superconducting behavior of BCS superconducting C-based materials, which demonstrate a phenomenal enhancement in the presence of shallow-level energy states.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Relativistic MR–MP Energy Levels for L-shell Ions of Silicon

Level energies are reported for Si v, Si vi, Si vii, Si viii, Si ix, Si x, Si xi, and Si xii. The energies have been calculated with the relativistic Multi-Reference Møller–Plesset Perturbation Theory method and include valence and K-vacancy states with nl up to 5f. The accuracy of the calculated level energies is established by comparison with the recommended data listed in the National Institute of Standards and Technology (NIST) online database. The average deviation of valence level energies ranges from 0.20 eV in Si v to 0.04 eV in Si xii. For K-vacancy states, the available values recommended in the NIST database are limited to Si xii and Si xiii. The average energy deviation is below 0.3 eV for K-vacancy states. The extensive and accurate data set presented here greatly augments the amount of available reference level energies. Here, we expect our data to ease the line identification of L-shell ions of Si in celestial sources and laboratory-generated plasmas, and to serve as energy references in the absence of more accurate laboratory measurements.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

Relativistic MR-MP Energy Levels for L-shell Ions of Sulfur and Argon

Calculated level energies for valence and K-vacancy states are given for the ion series S vii–S xiv and Ar ix–Ar xvi. The calculations were performed with the relativistic Multi-Reference Møller–Plesset Perturbation Theory method (MR-MP). The data set includes all the level energies with configurations $1{s}^{2}2{(s,p)}^{q}$, $1{s}^{2}2{(s,p)}^{q-1}{nl}$, $1{s}^{1}2{(s,p)}^{q+1}$, $1{s}^{1}2{(s,p)}^{q}{nl}$, $2{(s,p)}^{q+2}$, and $2{(s,p)}^{q+1}{nl}$, where 1 ≤ q ≤ 8, n ≤ 5, and l ≤ 3. We have compared our results with data from the National Institute of Standards and Technology (NIST) online database and with previous calculations. The average deviation of valence level energies ranges from 0.16 eV in Ne-like ions to 0.01 eV in Li-like ions, demonstrating that the present MR-MP valence level energies are highly accurate. In the case of K-vacancy states, the deviation is generally below 0.3 eV for Li-like S xiv and Ar xvi. The deviation for K-vacancy energies in other L-shell ions (Be-, B-, C-, N-, and O-like Ar ions) is higher but likely because the NIST-recommended values have a higher uncertainty. The data set includes many n = 4 and n = 5 valence and K-vacancy levels in L-shell ions of S and Ar that have not been previously reported. The data can be used for line identification and modeling of L-shell ions of S and Ar in astrophysical and laboratory-generated plasmas, and as energy references in the absence of more accurate laboratory calculations.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Next-Level Energy Management in Manufacturing: Facility-Level Energy Digital Twin Framework Based on Machine Learning and Automated Data Collection

This research introduces an energy prediction framework at the facility level supported by automated data collection and machine learning models. It investigates whether reducing the prediction time scale allows for applying more complex machine learning techniques and if those techniques improve the prediction accuracy. The primary advantages of this framework lie in its automation of the energy prediction process and its provision of real-time energy data suitable for use in energy dashboards or digital twins. A sitewide dataset was created by combining 15 min energy and daily production data of five shops—assembly, battery, body (electric), body (gas), and paint—from a globally recognized electric vehicle manufacturer. Various machine learning models were evaluated on daily, weekly, and monthly datasets, including, in increasingly complex order: naïve, simple linear regression, net regularized generalized linear regression, principal component regression, k-nearest neighbor, random forest, and Bayesian regularized neural network. Compared to the current state-of-the-art energy consumption prediction for the industrial facility level, this research investigates more complex models and smaller time intervals for higher accuracy. The findings revealed that the more complex monthly models require a minimum of a year and a half of data to operate, while weekly models demand a year of data to achieve improved accuracy. Daily models can operate with only six months of data but exhibit poor performance due to reduced prediction accuracy of production. Key challenges identified include access to reliable, high-quality energy and production data and the initial demand for human labor.

digital twin↗
DOE OSTI2024

Energy Levels of Light Nuclei A=13

Experimental nuclear spectroscopic data are evaluated for the 7 known nuclides of mass 13 (Li, Be, B, C, N, O, F). Detailed information is compiled and presented for each reaction and decay experiment. The results are combined and used to provide a set of recommended values that include level energies, spins and parities, half-lives of levels, decay branching ratios, and other nuclear properties. Furthermore, this work supersedes the earlier work by Fay Ajzenberg-Selove (1990Aj01) published in Nuclear Physics A 523 (1991) 1. Earlier reviews were published in (1986Aj01, 1981Aj01, 1976Aj04, 1970Aj04, 1959Aj76).

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

Expert Elicitation for Tidal Energy Levelized Cost of Energy: Present and Future

In accordance with the Government Performance and Results Act (GPRA), H2O annually assesses marine energy technology development resulting from government-funded research and development programs and strategy. For GPRA reporting, H2O uses the levelized cost of energy (LCOE) - which represents the total system cost per unit of energy produced - to measure the progression of marine energy technology development, assess the impact of their research and development programs, and identify future research priorities. To support H2O's GPRA reporting requirements and inform future strategy, the National Laboratory of the Rockies conducted a tidal energy LCOE expert elicitation study to estimate present and future LCOE[AB2.1]. This report describes the motivation and background for the elicitation study, the methodology used to conduct the study, and the study results. It also provides future recommendations for accelerated tidal energy LCOE reduction based on feedback from study participants.

16 TIDAL AND WAVE POWER↗
DOE OSTI2023

Effects of HAT-CN Layer Thickness on Molecular Orientation and Energy-Level Alignment with ZnPc

Efficient energy-level alignment is crucial for achieving high performance in organic electronic devices. Because the electronic structure of an organic semiconductor is significantly influenced by its molecular orientation, comprehensively understanding the molecular orientation and electronic structure of the organic layer is essential. In this study, we investigated the interface between a 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) hole injection layer and a zinc-phthalocyanine (ZnPc) p-type organic semiconductor. To determine the energy-level alignment and molecular orientation, we conducted in situ ultraviolet and X-ray photoelectron spectroscopies, as well as angle-resolved X-ray absorption spectroscopy. We found that the HAT-CN molecules were oriented relatively face-on (40°) in the thin (5 nm) layer, whereas they were oriented relatively edge-on (62°) in the thick (100 nm) layer. By contrast, ZnPc orientation was not significantly altered by the underlying HAT-CN orientation. The highest occupied molecular orbital (HOMO) level of ZnPc was closer to the Fermi level on the 100 nm thick HAT-CN layer than on the 5 nm thick HAT-CN layer because of the higher work function. Consequently, a considerably low energy gap between the lowest unoccupied molecular orbital level of HAT-CN and the HOMO level of ZnPc was formed in the 100 nm thick HAT-CN case. This may improve the hole injection ability of the anode system, which can be utilized in various electronic devices.

42 ENGINEERING↗
DOE OSTI2024

Molecular Precision Engineering for Efficient Binary Organic Photovoltaics through Energy Level and Fibrillar Structure Modulation

Adjusting the energy levels and fibrillar morphology is paramount to enhancing the power conversion efficiency (PCE) of organic solar cells (OSCs). In the present study, an increase in the open-circuit voltage (VOC) is facilitated through the elongation of the alkyl chain within AQx (namely AQx-8), aiming to decrease the free volume ratio (FVR). This reduction in FVR attenuates electron-phonon coupling, thereby augmenting emission efficiency and diminishing the non-radiative energy loss (ΔEnr). To further refine the energy levels and morphological characteristics, the external undecyl chain of AQx-8 is substituted with a shorter carbon chain and cyclohexane noted for its considerable steric hindrance (AQx-H). Additionally, this alteration significantly mitigates intermolecular aggregation, expands the bandgap, and elevates the lowest unoccupied molecular orbital (LUMO) energy level, culminating in an elevated VOC of 0.923 V in devices based on AQx-H. Morphological analysis reveals that blends based on AQx-H exhibit an enhanced multi-length-scale fibrillar structure, which is conducive to exciton dissociation and charge transport, thereby contributing to a high fill factor (FF) nearing 80%. Consequently, this study reports one of the highest binary PCEs documented, standing at 19.5% (with certification at 19.0%).

14 SOLAR ENERGY↗
DOE OSTI2020

Boson Fermion Nuclei Energy Levels In The Third Period Of The Periodic Table Of Elements (Monograph No.5)

The boson fermion nucleus (BFN) energy level is shown for sodium, magnesium, aluminum, silicon, phosphorus, sulphur, chlorine, and argon. The BFN energy levels are compared to the energy levels in the shell nuclear model. Individual nucleon fermions in the BFN make minor contributions to the nucleus energy level. Nucleons rearrange into boson structures during stellar nucleosynthesis and condense into the lowest-level energy state. Deconstruction of the BFN structure and conversion to a shell or liquid-drop model brings about a higher energy state. This is not favored in nature.

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

Lower energy levels and iodine-based material decomposition images increase pancreatic ductal adenocarcinoma conspicuity on rapid kV-switching dual-energy CT

Purpose: Multidetector computed tomography (MDCT) is used in the diagnosis of pancreatic ductal adenocarcinoma (PDAC), but it may be inadequate in some cases. Tumor detection can be improved using rapid kV-switching dual-energy CT (rsDECT) and iodine maps. Our aim this study is to evaluate tumor conspicuity in PDAC cases using rsDECT and iodine maps. Methods: Ninety cases with PDAC were evaluated rsDECT. Tumor contrast (HU) differences, tumor size, CNR (contrast-noise ratio), and noise were measured at 70 keV, individual CNR-energy level, and 45 keV, respectively. Quantitative differences in contrast gain ∆70-CNR and ∆CNR-45 were compared. On iodine maps, the iodine concentration measured in the tumor and parenchyma was normalized to the aorta as normalized iodine concentration (NIC) and compared. Results: The median optimized viewing energy level was 51 keV. The mean ± SD tumor contrast values were 62 ± 20, 115 ± 48, and 152 ± 48 HU (p < 0.001); the largest axial diameters were 36.6 ± 5.1, 37.9 ± 4.2, and 38.3 ± 3.7 mm (p = 0.015); the CNRs were 1.83 ± 0.72, 3.37 ± 0.93, and 2.36 ± 0.56; and the image noise levels were 23.7 ± 6.8, 39.3 ± 11.6, and 59.5 ± 17.2 (p < 0.001) (p < 0.001) for 70 keV, optimized energy level, and 45 keV, respectively. The mean ± SD contrast gain ∆70-CNR was 63 ± 12; and ∆CNR-45 was 31 ± 26 HU (p < 0.001). NIC{sub tumor} and NIC{sub parenchyma} values were 0.62 ± 0.03 and 1.36 ± 0.05 mg/mL, respectively (p = 0.004). Conclusion: The use of low energy levels on rsDECT and iodine maps improves tumor conspicuity. This situation may be help better detection of pancreatic tumors.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Energy Levels, Radiative Rates, and Lifetimes for Transitions in Fe XIV

Energy levels, transition rates, and lifetimes are reported for the low-lying 129 levels of Fe XIV, belonging to the n = 3 states (1s{sup 2}2s{sup 2}2p{sup 6})3s{sup 2}3p, 3s3p{sup 2}, 3s{sup 2}3d, 3p{sup 3}, 3s3p3d, 3p{sup 2}3d, 3s3d{sup 2}, and 3p3d{sup 2}. High-accuracy calculations have been performed as benchmarks in the request for accurate treatments of relativity, electron correlation and quantum electrodynamic (QED) effects in multi-valence-electron systems. The calculated energy levels are in excellent agreement with the experimental results and the experimentally compiled energy values, of the National Institute for Standards and Technology wherever available. The calculated values including core–valence correlation are found to be in good agreement with other theoretical and experimental values.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Multi-fidelity learning for interatomic potentials: low-level forces and high-level energies are all you need

The promise of machine learning interatomic potentials (MLIPs) has led to an abundance of public quantum mechanical (QM) training datasets. The quality of an MLIP is directly limited by the accuracy of the energies and atomic forces in the training dataset. Unfortunately, most of these datasets are computed with relatively low-accuracy QM methods, e.g. density functional theory with a moderate basis set. Due to the increased computational cost of more accurate QM methods, e.g. coupled-cluster theory with a complete basis set (CBS) extrapolation, most high-accuracy datasets are much smaller and often do not contain atomic forces. The lack of high-accuracy atomic forces is quite troubling, as training with force data greatly improves the stability and quality of the MLIP compared to training to energy alone. Because most datasets are computed with a unique level of theory, traditional single-fidelity (SF) learning is not capable of leveraging the vast amounts of published QM data. In this study, we apply multi-fidelity learning (MFL) to train an MLIP to multiple QM datasets of different levels of accuracy, i.e. levels of fidelity. Specifically, we perform three test cases to demonstrate that MFL with both low-level forces and high-level energies yields an extremely accurate MLIP—far more accurate than a SF MLIP trained solely to high-level energies and almost as accurate as a SF MLIP trained directly to high-level energies and forces. Therefore, MFL greatly alleviates the need for generating large and expensive datasets containing high-accuracy atomic forces and allows for more effective training to existing high-accuracy energy-only datasets. Indeed, low-accuracy atomic forces and high-accuracy energies are all that are needed to achieve a high-accuracy MLIP with MFL.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Inverse kinematics study of the energy levels of 21 Ne populated with the 20 Ne +𝑑 reaction

In recent years there has been significant experimental effort aimed at studying the impact of 16 O neutron poisoning on the weak 𝑠 process in rotating massive stars. Improving the understanding of energy levels in 21 Ne is crucial to reducing uncertainties in the rates of the 𝛼-induced reactions on 17 O that determine the overall efficiency of the weak 𝑠 process. This paper reports on one such experiment: a study of the 20 Ne (𝑑,𝑝)⁢ 21 Ne reaction in inverse kinematics. Deduced spin-parity assignments were made based on adiabatic distorted-wave approximation analysis and neutron partial widths were estimated by comparison with a previous experiment. Of particular significance for nuclear astrophysics is the resulting neutron partial width for the 7820-keV energy level, estimated to be 12 200 ⁢(2900)⁢ eV, and an upper limit of ≤ 9300 eV for that of the 7749-keV energy level. These results are in tension with previous studies and therefore this paper also discusses the current state of the research into the astrophysically relevant energy levels and highlights both areas of agreement and areas of disagreement between this and various other studies that have investigated this nucleus.

direct reactions↗
DOE OSTI2022

Polyimide as a durable cathode for all-solid-state Li(Na)–organic batteries with boosted cell-level energy density

The integration of organic electrode materials (OEMs) with solid-state electrolytes (SSEs) is expected to build an all-solid-state battery (ASSB) with long-term sustainability, high safety, and high energy density. Despite this great promise, the cell-level energy density is still far from practically applicable, which stems from the ultrathick SSE layer and thin cathode layer used in a pellet-type ASSB design. Here, a cost-effective polyimide (PI) material was first exploited as an organic cathode for sulfide-based ASSBs. A capacity of ~190 mAh g -1 was delivered with almost no capacity decay over 300 cycles. Moreover, for the first time, a dry-film approach was introduced to manufacture a sheet-type Li–organic ASSB with an ultrathin SSE layer and a high-areal-loading PI cathode. Notably, PI is a perfect candidate for dry-film technology due to its high thermal stability and extraordinary chemical inertness toward sulfide SSEs. Remarkably, the free-standing SSE membrane was merely 46 μm thick, and an ultralow areal resistance of 3.3 Ω cm 2 was achieved, more than tenfold lower than that of reported SSE pellets. One order of magnitude boost in the cell-level energy density was achieved. This work presents a significant leap in transferring organic ASSB technology from laboratory research to factory manufacturing.

25 ENERGY STORAGE↗
DOE OSTI2018

Energy levels, radiative transitions and Auger transitions of the core excited states for B-like ions

Highlights: • Core excited states from 1s2s{sup 2}2p{sup 2} and 1s2s2p{sup 3} for B-like systems are studied. • Energy levels, radiative transitions and Auger transitions are calculated. • Radiative and Auger rates are discussed with nuclear charge numbers. - Abstract: Energy levels, radiative transitions and Auger transitions of the core excited states from 1s2s{sup 2}2p{sup 2} and 1s2s2p{sup 3 2,4} L (L=S,P,D) configurations for B-like systems including P{sup 10+}, Ca{sup 15+}, Mn{sup 20+}, and Zn{sup 25+} ions are calculated using the saddle-point variation and saddle-point complex-rotation methods. The first-order perturbation theory is used to calculate relativistic and mass polarization corrections. Present energy levels, radiative transition rates and wavelengths, Auger rates and electron energies are compared with theoretical and experimental values in the literature. The total radiative rates and the total Auger rates for these resonances are also discussed with nuclear charge numbers.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

Energy levels and radiative rates for transitions in Cr-like Kr XIII, Tc XX and Xe XXXI

Energy levels, radiative transition probabilities, Landé g-factors, and radiative lifetimes are reported for 144 levels of the 3p{sup 6}3d{sup 6} and 3p{sup 5}3d{sup 7} configurations of the Cr-like ions Kr XIII, Tc XX and Xe XXXI. Since to our knowledge no prior data for energy levels or A-values, experimental or theoretical, are available in the literature for these ions, calculations have been performed with three independent atomic structure codes, namely GRASP, FAC and a code implementing the QR approach, with increasing configuration interaction (CI) basis with each code. This is to establish the accuracy of the calculated results so that data can be confidently applied in the modeling of plasmas. Our recommended data are determined within the QR approach, because not only has the largest CI basis been included in this calculation, the reliability has already been established in our earlier work for other Cr-like ions, for which some experimental and theoretical data were available for comparison. Results for radiative rates (A-values) and transition wavelengths (λ) are listed for all strong E1, E2 and M1 transitions among the 144 levels of each ion.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗