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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 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Directing High-Efficiency Na Plating with Carbon–Aluminum Junction Interfaces for Anode-Free Na Metal Batteries

Anode-free sodium metal batteries are highly promising for future energy storage but suffer from much faster cycling degradation as they are sensitive to even trace levels of irreversible side reactions. This work focuses on the most practical Al foil current collectors and systematically examined the effect of nano-sized carbon coating on improving the Na plating and stripping stability. We identified that the carbon-Al junction interface generated by carbon coating enabled more uniform Na depositing with lower overpotentials, delivering higher than 99.8% Faradaic efficiencies for a wide range of cycling currents between 0.5 and 3.0 mA cm -2 . This performance is much better than the 96.4% efficiency observed on uncoated Al foils under the same conditions, and was also confirmed under lean electrolyte and freezing electrolyte conditions, and can be attributed to the stronger interfacial binding and enhanced sodiophilic properties of the carbon-aluminum junction sites. Furthermore, these sites not only ensure uniform Na plating but also eliminates side reactions that would otherwise cause electrolyte depletion. As a result, Na-metal free full cells assembled with high capacity Na 3 V 2 (PO 4 ) 3 cathode delivered ~ 85% capacity retention for 100 cycles, higher than the 73% of retention of uncoated Al foil.

25 ENERGY STORAGE↗
DOE OSTI2025

Anode Potential Evolution During Zinc Metal Plating and Stripping in Dual-Solvent Battery Electrolytes

In the field of battery electrolyte research, the importance of the working cation solvation environment has become increasingly more apparent. To optimize bulk properties and, especially, interfacial reactions, multisolvent electrolytes (electrolytes containing two different solvents) have become more prevalent in battery research and development. In this work, we elucidate the relationship between cation solvation and interfacial electrochemistry, demonstrating that preferential solvation of Zn 2+ by a strong coordinating solvent such as 2-methoxyethylamine or ethylenediamine as opposed to a weaker solvent such as 3-methylsulfolane or acetonitrile leads to dynamic evolution in the interfacial energetics during Zn plating and stripping due to local changes in solvent composition and coordination. In some instances, interfacial solvation evolution can shift the reversible potential of Zn plating by as much as 1 V under relatively mild rate conditions. Through these investigations, we establish the generality of this phenomenon, highlight its importance as a consideration in dual-solvent battery electrolytes, and provide direction for tailoring electrochemistry through solvent design.

Hahn, Nathan T.↗
DOE OSTI2025

Learning robust parameter inference and density reconstruction in flyer plate impact experiments

Estimating physical parameters or material properties from experimental observations is a common objective in many areas of physics and material science. In many experiments, especially in shock physics, radiography is the primary means of observing the system of interest. However, radiography does not provide direct access to key state variables, such as density, which prevents the application of traditional parameter estimation approaches. Here we focus on flyer plate impact experiments on porous materials, and resolving the underlying parameterized equation of state (EoS) and crush porosity model parameters given radiographic observation(s). We use machine learning as a tool to demonstrate with high confidence that using only high impact velocity data does not provide sufficient information to accurately infer both EoS and crush model parameters, even with fully resolved density fields or a dynamic sequence of images. We thus propose an observable data set consisting of low and high impact velocity experiments/simulations that capture different regimes of compaction and shock propagation, and proceed to introduce a generative machine learning approach which produces a posterior distribution of physical parameters directly from radiographs. We demonstrate the effectiveness of the approach in estimating parameters from simulated flyer plate impact experiments, and show that the obtained estimates of EoS and crush model parameters can then be used in hydrodynamic simulations to obtain accurate and physically admissible density reconstructions. Finally, we examine the robustness of the approach to model mismatches, and find that the learned approach can provide useful parameter estimates in the presence of out-of-distribution radiographic noise and previously unseen physics, thereby promoting a potential breakthrough in estimating material properties from experimental radiographic images.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2016

Hydrothermal synthesis and characterization under dynamic conditions of cobalt oxide nanoparticles supported over magnesium oxide nano-plates

Here, a nano-catalyst comprised of oxidized Co NPs supported on MgO nano-plates was synthesized via a hydrothermal co-precipitation strategy and calcination in O 2 and subsequently in H 2 at 250 °C. Spectro-microscopy characterization was performed by scanning transmission electron microscopy, electron energy loss spectroscopy and scanning X-ray transmission microscopy. Surface measurements under H 2 and H 2 + CO atmospheres were obtained by ambient pressure X-ray photoelectron spectroscopy and in situ X-ray absorption spectroscopy in the 225–480 °C range. These measurements at the atomic and microscopic levels demonstrated that the oxidized Co nanoparticles uniformly decorated the MgO nano-plates. The surfaces are enriched with Co, and with a mixture of Co(OH) 2 and CoO under H 2 and H 2 + CO atmospheres. Under a H 2 atmosphere, the outermost surfaces were composed of (lattice) O 2- , CO 3 2- and OH - . No inorganic carbonates were observed in the bulk. Chemisorbed CO, likely on the oxidized Co surfaces, was observed at the expense of O 2- under 300 mTorr H 2 + CO (2:1) at 225 °C. Gas phase CO 2 was detected under 32 Torr H 2 + CO (2:1) at 225 °C upon prolonged reaction time, and was attributed to a surface chemical reaction between O 2- and chemisorbed CO. Furthermore, sp 3 like carbon species were detected on the otherwise carbon free surface in H 2 + CO, which remained on the surface under the subsequent reaction conditions. The formation of sp 3 like hydrocarbons was ascribed to a surface catalytic reaction between the chemisorbed CO and OH - as the apparent hydrogen source.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Electrolytic gold plating, stripping, and ion transport dynamics through a solid-state iodide perovskite

The pronounced electrochemical reactivity between halide perovskites and metal electrodes can introduce mobile extrinsic metal ions which can cause device instability or enable novel functionalities. Here we systematically investigate the kinetics of gold cation (Au + ) migration in indium tin oxide (ITO)/methylammonium lead triiodide (MAPbI 3 )/Au model devices under long-term potentiostatic biasing. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) analyses reveal that Au + ions, electrochemically generated at the Au anode, traverse the perovskite layer with diffusion coefficients on the order of 10 −11 to 10 −10 cm 2 s −1 and are subsequently reduced at the cathode as Au 0 clusters, resembling metal plating behavior in electrolytic cells and solid-state batteries during charging. Furthermore, reversing the applied bias strips the plated Au 0 , revealing reversibility suitable for bipolar resistive switching devices and providing direct evidence of the electrochemical and ionic nature of Au transport within the perovskite matrix. Quantitatively determining diffusion coefficients and ion concentrations provides foundational inputs for future drift-diffusion modelling opportunities and allows us to relate our findings to implications on long term operation of devices like photovoltaic modules. These results clearly demonstrate the solid-state electrochemical nature of perovskite devices, highlight methods to be more quantitative about ion transport properties, provide and emphasize the importance of disentangling electro-, photo-, photoelectrochemical processes for understanding device performance and unlocking new functionalities.

14 SOLAR ENERGY↗
DOE OSTI2013

Application of MMC model on simulation of shearing process of thick hot-rolled high strength steel plate

Shear operation is widely used as the first step in sheet metal forming to cut the sheet or plate into the required size. The shear of thick hot-rolled High Strength Steel (HSS) requires large shearing force and the sheared edge quality is relatively poor because of the large thickness and high strength compared with the traditional low carbon steel. Bad sheared edge quality will easily lead to edge cracking during the post-forming process. This study investigates the shearing process of thick hot-rolled HSS plate metal, which is generally exploited as the beam of heavy trucks. The Modified Mohr-Coulomb fracture criterion (MMC) is employed in numerical simulation to calculate the initiation and propagation of cracks during the process evolution. Tensile specimens are designed to obtain various stress states in tension. Equivalent fracture strains are measured with Digital Image Correlation (DIC) equipment to constitute the fracture locus. Simulation of the tension test is carried out to check the fracture model. Then the MMC model is applied to the simulation of the shearing process, and the simulation results show that the MMC model predicts the ductile fracture successfully.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Quasi-one-dimensional modes in strip plates: Theory and experiment

Using acoustic resonance spectroscopy we measure the elastic resonances of a strip rectangular plate with all its ends free. The experimental setup consist of a vector network analyzer, a high-fidelity audio amplifier, and electromagnetic-acoustic transducers. The one-dimensional modes are identified from the measured spectra by comparing them with theoretical predictions of compressional and bending modes of the plate modeled as a beam. The agreement between theory and experiment is excellent.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

Stochastic bifurcation and fractal and chaos control of a giant magnetostrictive film-shape memory alloy composite cantilever plate subjected to in-plane harmonic and stochastic excitation

Stochastic bifurcation and fractal and chaos control of a giant magnetostrictive film–shape memory alloy (GMF–SMA) composite cantilever plate subjected to in-plane harmonic and stochastic excitation were studied. Van der Pol items were improved to interpret the hysteretic phenomena of both GMF and SMA, and the nonlinear dynamic model of a GMF–SMA composite cantilever plate subjected to in-plane harmonic and stochastic excitation was developed. The probability density function of the dynamic response of the system was obtained, and the conditions of stochastic Hopf bifurcation were analyzed. The conditions of noise-induced chaotic response were obtained in the stochastic Melnikov integral method, and the fractal boundary of the safe basin of the system was provided. Finally, the chaos control strategy was proposed in the stochastic dynamic programming method. Numerical simulation shows that stochastic Hopf bifurcation and chaos appear in the parameter variation process. The boundary of the safe basin of the system has fractal characteristics, and its area decreases when the noise intensifies. The system reliability was improved through stochastic optimal control, and the safe basin area of the system increased.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

The effects of magnetohydrodynamic and radiation on flow of second grade fluid past an infinite inclined plate in porous medium

An analysis of the exact solutions of second grade fluid problem for unsteady magnetohydrodynamic (MHD) flows past an infinite inclined plate in a porous medium is presented. It is assumed that the bounding infinite inclined plate has a constant temperature with radiation effects. Based on Boussinesq approximation the expressions for dimensionless velocity, temperature and concentration are obtained by using Laplace transform method. The derived solutions satisfying the involved differential equations, and all the boundary and initial conditions. The influence of various parameters on the velocity has been illustrated graphically and analyzed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Study the effect of chemical reaction and variable viscosity on free convection MHD radiating flow over an inclined plate bounded by porous medium

An analysis is performed to study the free convection heat and mass transfer flow of an electrically conducting incompressible viscous fluid about a semi-infinite inclined porous plate under the action of radiation, chemical reaction in presence of magnetic field with variable viscosity. The dimensionless governing equations are steady, two-dimensional coupled and non-linear ordinary differential equation. Nachtsgeim-Swigert shooting iteration technique along with Runge-Kutta integration scheme is used to solve the non-dimensional governing equations. The effects of magnetic parameter, viscosity parameter and chemical reaction parameter on velocity, temperature and concentration profiles are discussed numerically and shown graphically. Therefore, the results of velocity profile decreases for increasing values of magnetic parameter and viscosity parameter but there is no effect for reaction parameter. The temperature profile decreases in presence of magnetic parameter, viscosity parameter and Prandtl number but increases for radiation parameter. Also, concentration profile decreases for the increasing values of magnetic parameter, viscosity parameter and reaction parameter. All numerical calculations are done with respect to salt water and fixed angle of inclination of the plate.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Three-dimensional particle-in-cell simulation on gain saturation effect of microchannel plate

We present here the results of the simulation work, using the three-dimensional particle-in-cell method, on the performance of the lead glass microchannel plate under saturated state. We calculated the electron cascade process with different DC bias voltages under both self-consistent condition and non-self-consistent condition. The comparative results have demonstrated that the strong self-consistent field can suppress the cascade process and make the microchannel plate saturated. The simulation results were also compared to the experimental data and good agreement was obtained. The simulation results also show that the electron multiplication process in the channel is accompanied by the buildup process of positive charges in the channel wall. Though the interactions among the secondary electron cloud in the channel, the positive charges in the channel wall, and the external acceleration field can make the electron-surface collision more frequent, the collision energy will be inevitably reduced, thus the electron gain will also be reduced.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Near-field radiative heat transfer between doped-Si parallel plates separated by a spacing down to 200 nm

Heat transfer between two objects separated by a nanoscale vacuum gap holds great promise especially in energy harvesting applications such as near-field thermophotovoltaic systems. However, experimental validation of nanoscale radiative heat transfer has been largely limited to tip-plate configurations due to challenges of maintaining small gap spacing over a relatively large area. Here in this paper, we report measurements of heat transfer near room temperature between two 1 cm by 1 cm doped-Si parallel plates, separated by a vacuum gap from about 200 nm to 780 nm. The measured strong near-field radiative transfer is in quantitative agreement with the theoretical prediction based on fluctuational electrodynamics. The largest measured radiative heat flux is 11 times as high as the blackbody limit for the same hot and cold surface temperatures. Our experiments have produced the highest radiative heat transfer rate observed to date across submicron distances between objects near room temperature.

42 ENGINEERING↗
DOE OSTI2019

Response of a lead-free borosilicate-glass microchannel plate to 14-MeV neutrons and γ-rays

In microchannel plate applications, such as in space telescopes, night-vision devices, or time-of-flight particle detection, reducing the sensitivity to signals from background sources, such as γ-rays, is beneficial for the system design and performance. The response of a single-stage lead-free borosilicate-glass microchannel plate to 14-MeV neutrons and γ-rays produced via (n, γ) reactions in surrounding structures was investigated at OMEGA. The average efficiency values for secondary electron production were found to be (5.1 ± 0.7) × 10−3 for 14-MeV neutrons and (4.9 ± 1.1) × 10−3 for ⟨1.5⟩-MeV γ-rays.

Parker, C. E. (ORCID:0000000303626984)↗
DOE OSTI2019

Modifications produced on a large magnetized plasma column by a floating end-plate that is partially emissive: Experiment and theory

An experiment is performed on a large plasma device operated by the Basic Plasma Science Facility at the University of California, Los Angeles, in which an electrically floating structure is placed near the end of the 18-m magnetized plasma column. The structure consists of a flat carbon plate that acts as a mask for a smaller, ring-shaped LaB6 emissive surface whose temperature can be externally controlled. This configuration has been previously used to study electron heat transport and pressure-driven avalanches [B. Van Compernolle and G. J. Morales, Phys. Plasmas 24, 112302 (2017)] by biasing the LaB6 ring-cathode with respect to a distant anode in a cold afterglow plasma. In contrast, the present study is performed during the active portion of the steady-state discharge in which the nominal plasma parameters are determined by the injection of an electron beam from a BaO cathode at the opposite end. It is found that, even without an applied bias on the LaB6 cathode, the self-consistent potential and current profiles are modified near the end plate as the LaB6 temperature is increased, resulting in density increases on the field lines in contact with the ring-cathode. In the absence of enhanced ionization, at the largest cathode temperatures, the ambient density can be doubled. A theoretical model is presented that provides a quantitative explanation for the experimental observations.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Evaluation of temperature changes in a cell culture plate well with absorbing walls containing a 3D model of tumour spheroid under irradiation in the optical range

The temperature conditions for photodynamic therapy of the culture of tumour cells organised in 3D spheroids are studied. The spheroids are placed in the cell culture medium in the well of a special cell culture plate with absorbing walls. A mathematical model is presented that describes the temperature distribution in a well with a cell culture plate heated by optical radiation. It is shown that the temperature in the well volume is not uniformly distributed, and the temperature on the well surface can differ significantly from the temperature in its volume. (laser medicine)

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Friction stir welding of thick 7175 aluminium alloy plates for deepwater riser applications

To substantially reduce the cost of extracting petroleum from ultra-deepwater sources, manufacturing risers from 7175 aluminium (Al) alloys rather than steels is being considered. Friction stir welding (FSW), a solid-phase joining technique, is widely applied to 7XXX Al alloys because its mechanical properties are retained within the nugget zone. And, the primary technical objective of the current study is the development of high-strength, corrosion-resistant weldments that connect 7175 Al riser flanges and pipes. However, as the welding thickness increases, the welding speed can be greatly impeded, which lowers the manufacturing efficiency and weakens the mechanical properties in the heat affected zone (next to the nugget). Therefore, obtaining high-performance thick plate 7175 Al alloy joints via FSW is challenging. To overcome this dilemma, the current work optimises the tool design and welding parameters for achieving high-performance joints between 25.4 mm thick 7175 Al alloy plates in butt joint configuration.

Wang, Tianhao↗
DOE OSTI2017

Plasma q -plate for generation and manipulation of intense optical vortices

An optical vortex is a light wave with a twisting wavefront around its propagation axis and null intensity in the beam center. Its unique spatial structure of field lends itself to a broad range of applications, including optical communication, quantum information, superresolution microscopy, and multidimensional manipulation of particles. However, accessible intensity of optical vortices have been limited to material ionization threshold. This limitation might be removed by using the plasma medium. Here in this paper, we propose the design of suitably magnetized plasmas which, functioning as a q-plate, leads to a direct conversion from a high-intensity Gaussian beam into a twisted beam. A circularly polarized laser beam in the plasma accumulates an azimuthal-angle-dependent phase shift and hence forms a twisting wavefront. Our three-dimensional particle-in-cell simulations demonstrate extremely high-power conversion efficiency. The plasma q-plate can work in a large range of frequencies spanning from terahertz to the optical domain.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Large-surface-area diamond (111) crystal plates for applications in high-heat-load wavefront-preserving X-ray crystal optics

Fabrication and results of high-resolution X-ray topography characterization of diamond single-crystal plates with large surface area (10 mm × 10 mm) and (111) crystal surface orientation for applications in high-heat-load X-ray crystal optics are reported. The plates were fabricated by laser-cutting of the (111) facets of diamond crystals grown using high-pressure high-temperature methods. The intrinsic crystal quality of a selected 3 mm × 7 mm crystal region of one of the studied samples was found to be suitable for applications in wavefront-preserving high-heat-load crystal optics. Wavefront characterization was performed using sequential X-ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking-curve topography. In conclusion, the variations of the rocking-curve width and peak position measured with a spatial resolution of 13 µm × 13 µm over the selected region were found to be less than 1 µrad.

36 MATERIALS SCIENCE↗