D-RM Builder: A software tool for generating fast and accurate nonlinear dynamic reduced models from high-fidelity models
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Carbon capture↗
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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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An adaptive ANOVA-based PCKF for high-dimensional nonlinear inverse modeling
The probabilistic collocation-based Kalman filter (PCKF) is a recently developed approach for solving inverse problems. It resembles the ensemble Kalman filter (EnKF) in every aspect—except that it represents and propagates model uncertainty by polynomial chaos expansion (PCE) instead of an ensemble of model realizations. Previous studies have shown PCKF is a more efficient alternative to EnKF for many data assimilation problems. However, the accuracy and efficiency of PCKF depends on an appropriate truncation of the PCE series. Having more polynomial chaos basis functions in the expansion helps to capture uncertainty more accurately but increases computational cost. Selection of basis functions is particularly important for high-dimensional stochastic problems because the number of polynomial chaos basis functions required to represent model uncertainty grows dramatically as the number of input parameters (random dimensions) increases. In classic PCKF algorithms, the PCE basis functions are pre-set based on users' experience. Also, for sequential data assimilation problems, the basis functions kept in PCE expression remain unchanged in different Kalman filter loops, which could limit the accuracy and computational efficiency of classic PCKF algorithms. To address this issue, we present a new algorithm that adaptively selects PCE basis functions for different problems and automatically adjusts the number of basis functions in different Kalman filter loops. The algorithm is based on adaptive functional ANOVA (analysis of variance) decomposition, which approximates a high-dimensional function with the summation of a set of low-dimensional functions. Thus, instead of expanding the original model into PCE, we implement the PCE expansion on these low-dimensional functions, which is much less costly. We also propose a new adaptive criterion for ANOVA that is more suited for solving inverse problems. The new algorithm was tested with different examples and demonstrated great effectiveness in comparison with non-adaptive PCKF and EnKF algorithms.
97 MATHEMATICS AND COMPUTING↗
High pressure effects on EBC systems in high temperature environments
Environmental barrier coatings (EBCs) are designed to protect SiCfiber/SiCmatrix ceramic matrix composites (CMCs) in turbine engines by mitigating wear in high-temperature water vapor environments. The failure of EBCs is frequently attributed to the accelerated oxidation of the silicon bond coating layer when exposed to high-temperature steam, leading to the formation of a thickened thermally grown oxide (TGO). TGO growth increases interfacial stress, weakens adhesion, and results in coating spallation. Understanding the impact of high-temperature oxidation of EBC systems is essential for developing accurate lifespan models for turbine components, although pressurized oxidation testing is extremely sparse in the open literature. In this work, oxidation tests were performed on rare earth silicate EBCs coated onto SiC substrates under increased pressure conditions. The coated specimens were tested at 1100°C, 1200°C, and 1300°C at both 1 atm and 10 atm total pressure in steam environments. Subsequent characterization focused on the microstructural evolution of the EBC/Si/SiC system. The experimental findings indicated that TGO behavior is dependent on high-pressure conditions, with elevated pressure leading to an increase in oxide scale thickness and modifications in its morphology.
Ardrey, Kristyn [ORNL] (ORCID:0000000184407796)↗
High-energy and ultra-high-energy neutrinos: A Snowmass white paper
Astrophysical neutrinos are excellent probes of astroparticle physics and high-energy physics. With energies far beyond solar, supernovae, atmospheric, and accelerator neutrinos, high-energy and ultra-high-energy neutrinos probe fundamental physics from the TeV scale to the EeV scale and beyond. They are sensitive to physics both within and beyond the Standard Model through their production mechanisms and in their propagation over cosmological distances. They carry unique information about their extreme non-thermal sources by giving insight into regions that are opaque to electromagnetic radiation. Here in this white paper describes the opportunities astrophysical neutrino observations offer for astrophysics and high-energy physics, today and in coming years.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Tensile behavior of dual-phase titanium alloys under high-intensity proton beam exposure: radiation-induced omega phase transformation in Ti-6Al-4V
A high-intensity proton beam exposure with 181 MeV energy has been conducted at Brookhaven Linac Isotope Producer facility on various material specimens for accelerator targetry applications, including titanium alloys as a beam window material. The radiation damage level of the analyzed capsule was 0.25 dpa at the beam center region with an irradiation temperature around 120 oC. Tensile tests showed increased hardness and a large decrease in ductility for the dual a+ß-phase Ti-6Al-4V Grade-5 and Grade-23 extra low interstitial alloys, with the near a-phase Ti-3Al-2.5V Grade-9 alloy still exhibiting uniform elongation of a few % after irradiation. Transmission Electron Microscope analyses on Ti-6Al-4V indicated clear evidence of a high-density of defect clusters with size less than 2 nm in each a-phase grain. The ß-phase grains did not contain any visible defects such as loops or black dots, while the diffraction patterns clearly indicated ?-phase precipitation in an advanced formation stage. The radiation-induced ?-phase transformation in the ß-phase could lead to greater loss of ductility in Ti-6Al-4V alloys in comparison with Ti-3Al-2.5V alloy with less ß-phase.google scho
Tensile Test, titanium, acclerator, proton beam↗
Identifying high-impact and high-uncertainty parameters in MiniFuel model predictions
The MiniFuel irradiation platform at Oak Ridge National Laboratory's High Flux Isotope Reactor (HFIR) is a flexible, high-throughput separate effects test capability. Finite element thermal models are relied upon to design MiniFuel experiments and to achieve experimental objectives. Recent reports show good agreement in the model prediction of target fuel temperatures, but as the capability of the experiments is extended to higher temperatures, the uncertainty in the model predictions must be quantified. To that end, high-impact, high-uncertainty parameters that contribute the most uncertainty to the model are identified. The uncertainty quantification was accomplished through a series of screening and sensitivity analyses. The first analysis utilizes the method of Morris to perform a computationally efficient preliminary screening that considers uncertainty in a large number of the model inputs. The most important parameters identified in the Morris screening study were then considered in a Sobol sensitivity analysis that more robustly ranks and quantifies the uncertainty associated with each parameter. From these analyses, it was determined that thermal contact conductance between components is the parameter that contributes the highest uncertainty. The estimated uncertainty of the MiniFuel model fuel temperature predictions is ±80 °C in the removable beryllium and ±40 °C in the vertical experiment facilities. In conclusion, the framework established by the series of sensitivity analyses presented herein could easily be adapted to fit the needs of accelerated fuel qualification processes.
Fuel, Irradiation↗
Determination of the phase boundary of the omega to beta transition in Zr using in situ high-pressure and high-temperature X-ray diffraction
The high-pressure behavior of zirconium has been examined using the synchrotron X-ray diffraction technique to a pressure of 38 GPa and a temperature of 800 K employing a hydrothermal diamond anvil cell technique. The structural transition from the ω to the β phase was observed. This transition has a negative dP/dT gradient, which is in general agreement with those reported in previous studies. The transition boundary was determined to be, P (GPa)=41.2–0.025×T (K). The negative slope of the transition, dP/dT, determined in our study using the diamond anvil cell technique was less than half that estimated by the previous study using a large press apparatus. - Graphical abstract: Experimental results and phase boundary of the ω–β transition in Zr. - Highlights: • X-ray diffraction patterns of zirconium were measured by the synchrotron experiments. • High-pressure experiments were performed by an external-heated diamond anvil cell. • Phase diagram of zirconium was determined at high pressures and high temperatures. • Phase boundary between omega and beta transition has a negative dP/dT slope.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
High-temperature, high-pressure hydrothermal synthesis, characterization, and structural relationships of mixed-alkali metals uranyl silicates
Three mixed-alkali metals uranyl silicates, Na{sub 3}K{sub 3}[(UO{sub 2}){sub 3}(Si{sub 2}O{sub 7}){sub 2}]·2H{sub 2}O (1), Na{sub 3}Rb{sub 3}[(UO{sub 2}){sub 3}(Si{sub 2}O{sub 7}){sub 2}] (2), and Na{sub 6}Rb{sub 4}[(UO{sub 2}){sub 4}Si{sub 12}O{sub 33}] (3), have been synthesized by high-temperature, high-pressure hydrothermal reactions at 550 °C and 1440 bar, and characterized by single-crystal X-ray diffraction, photoluminescence, and thermogravimetric analysis. Compound 1 and 2 are isostructural and contain layers of uranyl disilicate. The smaller cation, Na{sup +}, is located in the intralayer channels, whereas the larger cations, K{sup +} and Rb{sup +}, and water molecule are located in the interlayer region. The absence of lattice water in 2 can be understood according to the valence-matching principle. The structure is related to that of a previously reported mixed-valence uranium(V,VI) silicate. Compound 3 adopts a 3D framework structure and contains a unique unbranched dreier fourfold silicate chain with the structural formula {uB,4"1_∞}[{sup 3}Si{sub 12}O{sub 33}] formed of Q{sup 2}, Q{sup 3}, and Q{sup 4} Si. The connectivity of the Si atoms in the Si{sub 12}O{sub 33}{sup 18−} anion can be interpreted on the basis of Zintl–Klemm concept. Crystal data for compound 1: triclinic, P-1, a=5.7981(2) Å, b=7.5875(3) Å, c=12.8068(5) Å, α=103.593(2)°, β=102.879(2)°, γ=90.064(2)°, V=533.00(3) Å{sup 3}, Z=1, R1=0.0278; compound 2: triclinic, P-1, a=5.7993(3) Å, b=7.5745(3) Å, c=12.9369(6) Å, α=78.265(2)°, β=79.137(2)°, γ=89.936(2)°, V=546.02(4) Å{sup 3}, Z=1, R1=0.0287; compound 3: monoclinic, C2/m, a=23.748(1) Å, b=7.3301(3) Å, c=15.2556(7) Å, β=129.116(2)°, V=2060.4(2) Å{sup 3}, Z=2, R1=0.0304. - Graphical abstract: Three mixed-alkali metals uranyl silicates were synthesized under hydrothermal conditions at 550 °C and 1400 bar and structurally characterized by single-crystal X-ray diffraction. Two of them have a layer structure with the alkali metal cations within and between the layers. The third one adopts a 3D framework structure and contains a unique unbranched dreier fourfold silicate chain formed of Q{sup 2}, Q{sup 3}, and Q{sup 4} Si. - Highlights: • Three new mixed-alkali metals uranyl silicates were synthesized by high-T, high-P hydrothermal method and structurally. • Two compounds adopt a layer structure and the third one has a 3D framework structure. • The 3D framework structure contains a unique unbranched dreier fourfold silicate chain formed of Q{sup 2}, Q{sup 3}, and Q{sup 4} Si.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Effect of Nb and Cu on the high temperature creep properties of a high Mn–N austenitic stainless steel
The effect of Nb and Cu addition on the creep properties of a high Mn–N austenitic stainless steel was investigated at 600 and 650 °C. In the original high Mn–N steel, which was initially precipitate-free, the precipitation of M{sub 23}C{sub 6} (M = Cr, Fe) and Cr{sub 2}N took place mostly on grain boudaries during creep deformation. On the other hand, the minor addition of Nb resulted in high number density of Z-phases (CrNbN) and MX (M = Nb; X = C, N) carbonitrides inside grains by combining with a high content of N, while suppressing the formation of Cr{sub 2}N. The addition of Cu gave rise to the independent precipitation of nanometer-sized metallic Cu particles. The combination of the different precipitate-forming mechanisms associated with Z-phase, MX and Cu-rich precipitates turned out to improve the creep-resistance significantly. The thermodynamics and kinetics of the precipitation were discussed using thermo-kinetic simulations. - Highlights: • The creep rupture life was improved by Nb and Cu addition. • The creep resistance of the steel A2 in this study was comparable to that of TP347HFG. • The size of Z-phase and MX carbonitride did not change significantly after creep test. • The nanometer sized Cu-rich precipitate was observed after creep. • The predicted size of precipitates by MatCalc agreed well with measured size.
36 MATERIALS SCIENCE↗
Graphitic carbon nitride nanosheets as highly efficient photocatalysts for phenol degradation under high-power visible LED irradiation
Highlights: • Bulk g-C{sub 3}N{sub 4} and its exfoliated form have been synthesized at different temperatures and characterized in detail. • Exfoliation proces increased oxidizing power of holes and enabled direct phenol degradation. • High-power visible LEDs improved significantly photocatalytic production of H{sub 2}O{sub 2} over exfoliated g-C{sub 3}N{sub 4}. • Synergistic effect between LEDs and exfoliated g-C{sub 3}N{sub 4} materials was observed. - Abstract: Exfoliated g-C{sub 3}N{sub 4} materials were prepared by thermal treatment of bulk materials synthesized from melamine at 4 different temperatures in range from 500 to 600 °C. The exfoliated g-C{sub 3}N{sub 4} synergically increased the photocatalytic degradation of phenol as effects like the fast production of H{sub 2}O{sub 2}, the presence of more active holes for direct phenol degradation and the use of high-power visible (416 nm) LEDs as irradiation source. The amount of phenol initially present was 99% converted in 15 min. All materials were also tested for comparison only in UVA region by using high-power UV (370 nm) LEDs. All prepared materials were thoroughly characterized by several analytical methods. In this work, the combination of g-C{sub 3}N{sub 4} after thermal treatment and high-power visible LEDs reduced the time needed for complete phenol degradation from several hours to just a few minutes. The mechanism of phenol degradation was also studied by introducing different active species scavengers into the reaction medium.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
High thermoelectric performance of n-type PbTe 1-y S y due to deep lying states induced by indium doping and spinodal decomposition
Good thermoelectric materials should have high engineering figure-of-merit (ZT) eng , not peak ZT, to achieve high conversion efficiency. In this work, we achieved a good (ZT) eng by optimizing the carrier concentration to improve the room temperature ZT using deep lying dopant, indium, in PbTe 1-y S y . It was found that a room temperature ZT as high as ~0.5 and a peak ZT ~1.1 at about 673 K were obtained in Pb 0.98 In 0.02 Te 0.8 S 0.2 due to a lower thermal conductivity by alloy scattering and Spinodal decomposition. The calculated efficiency could be as high as ~12% at cold side 323 K and hot side 773 K. The approach is expected to work in other materials systems too.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
A high-voltage rechargeable magnesium-sodium hybrid battery
Growing global demand of safe and low-cost energy storage technology triggers strong interests in novel battery concepts beyond state-of-art Li-ion batteries. Here we report a high-voltage rechargeable Mg–Na hybrid battery featuring dendrite-free deposition of Mg anode and Na-intercalation cathode as a low-cost and safe alternative to Li-ion batteries for large-scale energy storage. A prototype device using a Na3V2(PO4)3 cathode, a Mg anode, and a Mg–Na dual salt electrolyte exhibits the highest voltage (2.60 V vs. Mg) and best rate performance (86% capacity retention at 10C rate) among reported hybrid batteries. Synchrotron radiation-based X-ray absorption near edge structure (XANES), atomic-pair distribution function (PDF), and high-resolution X-ray diffraction (HRXRD) studies reveal the chemical environment and structural change of Na3V2(PO4)3 cathode during the Na ion insertion/deinsertion process. XANES study shows a clear reversible shift of vanadium K-edge and HRXRD and PDF studies reveal a reversible two-phase transformation and V–O bond length change during cycling. The energy density of the hybrid cell could be further improved by developing electrolytes with a higher salt concentration and wider electrochemical window. This work represents a significant step forward for practical safe and low-cost hybrid batteries.
Li, Yifei↗
A highly stable host for lithium metal anode enabled by Li9Al4-Li3N-AlN structure
Not Available
Peng, Zhe↗
An Internal ALD-Based High Voltage Divider and Signal Circuit for MCP-based Photodetectors
We describe a pin-less design for the high voltage (HV) resistive divider of the all-glass LAPPD (TM) 8 in,square thin photodetector module. The divider, which distributes high voltage applied to the photocathode to the two micro-channel plates (MCPs) that constitute the amplification stage, is comprised of the two MCPs and three glass mechanical spacers, each of which is coated with a resistive layer using atomic layer deposition (ALD). The three glass grid spacers and the two MCPs form a continuous resistive path between cathode and anode, with the voltages across the MCPs and the spacers determined by the resistance of each. High voltage is applied on an external tab on the top glass window that connects to the photocathode through the metal seal. The DC ground is supplied by microstrips on the bottom glass plate that form the high-bandwidth anode. The microstrips exit the package through the glass-frit seal of the anode base-plate and the package sidewall. The divider is thus completely internal, with no HV pins penetrating the low-profile flat glass package. Measurements of the performance of the divider are presented for the 8 in.-square MCP and spacer package in a custom test fixture and for an assembled externally pumped LAPPD (TM) prototype with an aluminum photocathode. (C) 2015 Elsevier B.V. All rights reserved.
Adams, Bernhard W.↗
A concept for polarized 3 He targets for high luminosity scattering experiments in high magnetic field environments
In this work, we present the conceptual design of a polarized 3 He target to be used for high luminosity scattering experiments within high magnetic field environments. This two-cell target will take advantage of advancements in optical pumping techniques at high magnetic field to create 60% longitudinally polarized 3 He gas in a pumping cell within a uniform magnetic field above 1 T. By transferring the polarized gas to a cryogenic target cell, the gas density is increased to create a target thickness suitable for high luminosity applications. We discuss the general design of this scheme, and plans for its application in Jefferson Lab’s CLAS12 detector.
3He polarization↗
Advanced surface treatments for medium-velocity superconducting cavities for high-accelerating gradient continuous-wave operation
Not Available
McGee, K. (ORCID:0000000340572778)↗