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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 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Survival function analysis of planet size distribution with Gaia Data Release 2 updates

Applying the survival function analysis to the planet radius distribution of the Kepler confirmed/candidate planets, we have identified two natural divisions of planet radius at 4 Earth radii (R ⊕ ) and 10 R ⊕ . These divisions place constraints on planet formation and interior structure model. The division at 4 R ⊕ separates small exoplanets from large exoplanets above. When combined with the recently discovered radius gap at 2 R ⊕ , it supports the treatment of planets in between 2 and 4 R ⊕ as a separate group, likely water worlds. For planets around solar-type FGK main-sequence stars, we argue that 2 R ⊕ is the separation between water-poor and water-rich planets, and 4 R ⊕ is the separation between gas-poor and gas-rich planets. Here, we confirm the slope of the survival function in between 4 and 10 R ⊕ to be shallower compared to either ends, indicating a relative paucity of planets in between 4 and 10 R ⊕ , namely the sub-Saturnian desert there. We name them transitional planets, as they form a bridge between the gas-poor small planets and gas giants. Accordingly, we propose the following classification scheme: (<2 R ⊕ ) rocky planets, (2–4 R ⊕ ) water worlds, (4–10 R ⊕ ) transitional planets, and (>10 R ⊕ ) gas giants.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

First model-independent Dalitz analysis of B 0 → DK* 0 , D→K$^{0}_{S}$π + π – decay

We report a measurement of the amplitude ratio r S of B 0 → D 0 K* 0 and B 0 → D 0 ¯K* 0 decays with a Dalitz analysis of D → K$^{0}_{S}$π + π – decays, for the first time using a model-independent method. We set an upper limit rS<0.87 at the 68\% confidence level, using the full data sample of 772×10 6 BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB e + e – collider. This result is obtained from observables x–= +0.4$^{+1.0+0.0}_{–0.6–0.1}$ ± 0.0, y– = –0.6$^{+0.8+0.1}_{–1.0–0.0}$ ± 0.1, x + = +0.1$^{+0.7+0.0}_{–0.4–0.1}$ ± 0.1 and y + = +0.3$^{+0.5+0.0}_{–0.8–0.1}$ ± 0.1, where x ± = r S cos(δ S ± Φ 3 ), y ± = r S sin(δ S ± Φ 3 ) and Φ 3 (δ S ) is the weak (strong) phase difference between B 0 → D 0 K* 0 and B 0 → D¯ 0 K* 0 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and P l a n c k . II. Cross-correlation measurements and cosmological constraints

Cross-correlations of galaxy positions and galaxy shears with maps of gravitational lensing of the cosmic microwave background (CMB) are sensitive to the distribution of large-scale structure in the Universe. Such cross-correlations are also expected to be immune to some of the systematic effects that complicate correlation measurements internal to galaxy surveys. We present measurements and modeling of the cross-correlations between galaxy positions and galaxy lensing measured in the first three years of data from the Dark Energy Survey with CMB lensing maps derived from a combination of data from the 2500 deg 2 SPT-SZ survey conducted with the South Pole Telescope and full-sky data from the Planck satellite. The CMB lensing maps used in this analysis have been constructed in a way that minimizes biases from the thermal Sunyaev Zel’dovich effect, making them well suited for cross-correlation studies. The total signal-to-noise of the cross-correlation measurements is 23.9 (25.7) when using a choice of angular scales optimized for a linear (nonlinear) galaxy bias model. Here we use the cross-correlation measurements to obtain constraints on cosmological parameters. For our fiducial galaxy sample, which consist of four bins of magnitude-selected galaxies, we find constraints of Ω m =0.272$^{+0.032}_{-0.052}$ and S 8 ≡σ8$\sqrt{Ω_m/0.3}$=0.736$^{+0.032}_{-0.028}$ (Ω m =0.245$^{+0.026}_{-0.044}$ and S 8 =0.734$^{+0.035}_{-0.028}$) when assuming linear (nonlinear) galaxy bias in our modeling. Considering only the cross-correlation of galaxy shear with CMB lensing, we find Ω m =0.270$^{+0.043}_{-0.061}$ and S 8 =0.740$^{+0.034}_{-0.029}$. Our constraints on S8 are consistent with recent cosmic shear measurements, but lower than the values preferred by primary CMB measurements from Planck.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Measurement of the CKM angle φ 1 in B 0 → D ¯ ( * ) 0 h 0 , D ¯ 0 → K S 0 π + π - decays with time-dependent binned Dalitz plot analysis

Here, we show a measurement of the C P -violation parameter φ 1 obtained in a time-dependent analysis of B 0 → D ¯ ( * ) 0 h 0 decays followed by D ¯ 0 → K S 0 π + π - decay. A model-independent measurement is performed using the binned Dalitz plot technique. The measured value is φ 1 = 11.7 ° ± 7.8 ° ( stat ) ± 2.1 ° ( syst ) . Treating sin 2 φ 1 and cos 2 φ 1 as independent parameters, we obtain sin 2 φ 1 = 0.43 ± 0.27 ( stat ) ± 0.08 ( syst ) and cos 2 φ 1 = 1.06 ± 0.33 ( stat ) - 0.15 + 0.21 ( syst ) . The findings are obtained with a full data sample of 772 × 1 0 6 B B ¯ pairs collected near the Υ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Dispatchable Virtual Oscillator Control for Decentralized Inverter-Dominated Power Systems: Analysis and Experiments: Preprint

This paper presents an analysis and experimental validation of dispatchable virtual oscillator control (dVOC) for inverter-dominated power systems. dVOC is a promising decentralized control strategy that requires only local measurements to induce grid-forming behavior with programmable droop characteristics. It is dispatchable -- i.e., the inverters can vary their power generation via user-defined power set-points and guarantees strong stability. To verify its feasibility, a testbed comprising multiple dVOC-programmed inverters with transmission line impedances is designed. With an embedded synchronization strategy, the dVOC inverters are capable of dynamic synchronization, black start operation, and transient grid voltage regulation with dynamic load sharing, and real-time-programmable droop characteristics for backward compatibility. All these features are experimentally verified.

14 SOLAR ENERGY↗
DOE OSTI2021

Quasi-Dynamic Electromagnetic Field Safety Analysis and Mitigation for High-Power Dynamic Wireless Charging of Electric Vehicles

Dynamic wireless charging of electric vehicles (EV) is an emerging charging technology to enable non-contact wireless charging while the vehicle is moving. Compared to stationary wireless charging, in-motion wireless charging involves dynamic processes in which an EV is passing over the charging pads (transmitters). This in motion process makes the dynamic electromagnetic (EM) environment more complicated, and EM safety needs to be ensured under all circumstances. This is due to the fact that the entire vehicle body may be exposed to magnetic fields while the vehicle moves over the energized transmitter. This paper investigates several typical charging scenarios when EVs approach, pass over, and move away from the charging pads. Quasi-dynamic models, which are preliminarily verified by coils’ inductance measurements, are developed to analyze the dynamic process. Based on the quasi-dynamic analysis, shielding solutions are also studied to ensure EM safety for the dynamic wireless charging processes.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

Feasibility Analysis of Converter-Interfaced Combined Heat and Power System

As a promising new design concept, the converter-interfaced combined heat and power (CHP) system is coupled to the bulk grid through a rectifier and a grid-ready tied inverter. Compared to the traditional directly-coupled CHP system, it removes the requirement for oversizing the CHP generator, limits the short-circuit contribution of the generator and simplifies the grid integration process of CHP system. This paper evaluates the economic benefits of this concept by calculating the annualized Return-on-Investment (ROI) and comparing it to the directly-coupled system. The economic analysis includes timeseries simulations to compute energy transactions with the bulk grid as well as sizing the equipment to calculate the capital and operational costs. Obtained results indicate that in majority of user cases evaluated, the converter-interfaced CHP systems can provide better ROI than directly-coupled systems. Given the additional technical benefits provided by inverter-based distributed energy resources (DERs), the proposed concept is proved to be technically viable and economically feasible.

03 NATURAL GAS↗
DOE OSTI2017

Field Quality and Fabrication Analysis of HQ02 Reconstructed Nb3Sn Coil Cross Sections

© 2017 IEEE. The U.S. LHC Accelerator Research Program (LARP) quadrupole HQ02 was designed and fully tested as part of the low-beta quad development for Hi-Lumi LHC. HQ02's design is well documented with full fabrication accounting along with full field analysis at low and high current. With this history, HQ02 is an excellent test bed for developing a methodology for measuring turn locations from magnet cross sections and comparing with CAD models and measured field. All four coils of HQ02 were cut in identical locations along the magnetic length corresponding to magnetic field measurement and coil metrology. A real-time camera and coordinate measuring equipment was used to plot turn corners. Measurements include systematic and random displacements of winding blocks and individual turns along the magnetic length. The range of cable shifts and the field harmonic range along the length are in agreement, although correlating turn locations and measured harmonics in each cross section is challenging.

Holik, Eddie Frank↗
DOE OSTI2023

Solar PV and BESS Plant-Level Voltage Control and Interactions: Experiments and Analysis

In real world operation, low-frequency oscillations associated with plant-level voltage control of inverter-based resources (IBRs) have been a concern of grid operators. Here, this research aims to demonstrate and analyze the effect of plant-level voltage control on system stability and potential interactions among IBRs. The experiment results of a 13.2-kV system interconnected with two IBRs—a 1-MW battery energy storage system (BESS) and a 430-kW solar photovoltaic (PV) plant—are presented. Both 0.5-Hz and 3-Hz oscillations become visible at certain conditions. The phenomenon is further explained by use of a feedback system consisting of the plant-level droop control and the effect of reactive power or var injection on voltage. The main components of the block diagram are obtained via frequency scan measurements. The analysis offers an understanding of the main contributors and other influencing factors of the 3-Hz and 0.5-Hz modes. It also reveals the role of the volt-var droop gain, the low-pass filter time constant, and the system impedance in stability.

14 SOLAR ENERGY↗
DOE OSTI2016

Analysis of In-Route Wireless Charging for the Shuttle System at Zion National Park

System right-sizing is critical to implementation of wireless power transfer (WPT) for electric vehicles. This study will analyze potential WPT scenarios for the electrification of shuttle buses at Zion National Park utilizing a modelling tool developed by the National Renewable Energy Laboratory called WPTSim. This tool uses second-by-second speed, location, and road grade data from the conventional shuttles in operation to simulate the incorporation of WPT at fine granularity. Vehicle power and state of charge are simulated over the drive cycle to evaluate potential system designs. The required battery capacity is determined based on the rated power at a variable number of charging locations. The outcome of this work is an analysis of the design tradeoffs for the electrification of the shuttle fleet with wireless charging versus conventional overnight charging.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2015

An Analysis Platform for Multiscale Hydrogeologic Modeling with Emphasis on Hybrid Multiscale Methods

One of the most significant challenges facing hydrogeologic modelers is the disparity between those spatial and temporal scales at which fundamental flow, transport and reaction processes can best be understood and quantified (e.g., microscopic to pore scales, seconds to days) and those at which practical model predictions are needed (e.g., plume to aquifer scales, years to centuries). While the multiscale nature of hydrogeologic problems is widely recognized, technological limitations in computational and characterization restrict most practical modeling efforts to fairly coarse representations of heterogeneous properties and processes. For some modern problems, the necessary level of simplification is such that model parameters may lose physical meaning and model predictive ability is questionable for any conditions other than those to which the model was calibrated. Recently, there has been broad interest across a wide range of scientific and engineering disciplines in simulation approaches that more rigorously account for the multiscale nature of systems of interest. In this paper, we review a number of such approaches and propose a classification scheme for defining different types of multiscale simulation methods and those classes of problems to which they are most applicable. Our classification scheme is presented in terms of a flow chart (Multiscale Analysis Platform or MAP), and defines several different motifs of multiscale simulation. Within each motif, the member methods are reviewed and example applications are discussed. We focus attention on hybrid multiscale methods, in which two or more models with different physics described at fundamentally different scales are directly coupled within a single simulation. Very recently these methods have begun to be applied to groundwater flow and transport simulations, and we discuss these applications in the context of our classification scheme. As computational and characterization capabilities continue to improve, we envision that hybrid multiscale modeling will become more common and may become a viable alternative to conventional single-scale models in the near future.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2018

Foaming during Nuclear Waste Melter Feeds Conversion to Glass: Application of Evolved Gas Analysis

During the final stages of batch-to-glass conversion in a waste-glass melter, gases evolving in the cold cap produce primary foam, the formation and collapse of which control the glass production rate via its effect on heat transfer to the reacting batch. We performed quantitative evolved gas analysis (EGA) for several HLW melter feeds with temperatures ranging from 100 °C to 1150 °C, the whole temperature span in a cold cap. EGA results were supplemented with visual observation of batch-to-glass transition using the feed expansion tests. Upon heating, most of the gases—mainly H2O, CO2, NO, NO2, N2 and O2—evolve at temperatures below 700 °C and escape directly to the atmosphere through open porosity. However, as open porosity closes when enough glass-forming melt appears at 720 °C, the residual gas evolution leads to the formation of primary foam. We found that primary foaming is mostly caused by the decomposition of residual carbonates, though oxygen evolution from iron-redox reaction can also play a role. We also show that the gas evolution shifts to a higher temperature when the heating rate increases. The implications for the mathematical modeling of foam layer in the cold cap are presented.

Hujova, Miroslava↗
DOE OSTI2020

Isotope-Specific Analysis of Neutron-Irradiated Lithium Aluminate Ceramics by Nuclear Magnetic Resonance Spectroscopy

The effects of neutron irradiation on lithium aluminate targets and the permeation of tritium into surrounding components are primary concerns in the development of materials for use in tritium production. The high specific activity and volatility of the tritium in activated samples greatly increase the challenges of experimental analysis. This paper reports the determination of the chemical forms and quantities of H-3 and Li-6 in irradiated and non-irradiated LiAlO2 by nuclear magnetic resonance (NMR) spectroscopy, and demonstrates that measurements can be performed in a non-destructive, safe manner to obtain isotope-selective, quantitative information on highly hazardous materials.

Tritium, solid state nuclear magnetic resonance sp↗
DOE OSTI2024

Case Studies and Parametric Analysis of Heliostat Performance With a Tradeoff-Informed Technoeconomic Analysis Metric

The Heliostat Consortium (HelioCon) was launched in 2021 to advance heliostat technology. Here this work presents a collection of baseline case studies for the technoeconomic analysis (TEA) of candidate heliostat improvements for concentrating solar power (CSP) and concentrated solar thermal (CST) systems that employ central receivers. The case studies we develop include a large-scale CSP plant, a smaller, modular CSP plant, and a small CST plant used for industrial process heat. In this work, we also propose a novel metric for TEA of a plant component technology that recasts relative changes in levelized system costs into component-specific capital cost budgets. This measure, which we refer to as the equivalent breakeven installed cost, is the maximum budget for the technology component that leads to improved levelized costs. Finally, we perform a parametric analysis to show the impact of candidate technologies on the levelized cost of heat and, by extension, equivalent breakeven installed cost.

14 SOLAR ENERGY↗
DOE OSTI2017

Structural Loads Analysis for Wave Energy Converters: Preprint

This study explores and verifies the generalized body-modes method for evaluating the structural loads on a wave energy converter (WEC). Historically, WEC design methodologies have focused primarily on accurately evaluating hydrodynamic loads, while methodologies for evaluating structural loads have yet to be fully considered and incorporated into the WEC design process. As wave energy technologies continue to advance, however, it has become increasingly evident that an accurate evaluation of the structural loads will enable an optimized structural design, as well as the potential utilization of composites and flexible materials, and hence reduce WEC costs. Although there are many computational fluid dynamics, structural analyses and fluid-structure-interaction (FSI) codes available, the application of these codes is typically too computationally intensive to be practical in the early stages of the WEC design process. The generalized body-modes method, however, is a reduced order, linearized, frequency-domain FSI approach, performed in conjunction with the linear hydrodynamic analysis, with computation times that could realistically be incorporated into the WEC design process. The objective of this study is to verify the generalized body-modes approach in comparison to high-fidelity FSI simulations to accurately predict structural deflections and stress loads in a WEC. Two verification cases are considered, a free-floating barge and a fixed-bottom column. Details for both the generalized body-modes models and FSI models are first provided. Results for each of the models are then compared and discussed. Finally, based on the verification results obtained, future plans for incorporating the generalized body-modes method into the WEC simulation tool, WEC-Sim, and the overall WEC design process are discussed.

17 WIND ENERGY↗