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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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Direct numerical simulation of a high-pressure turbulent reacting temporal mixing layer
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Mesoscale simulations of radiation damage effects in Materials: A SEAKMC perspective
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Lattice Boltzmann simulation of pressure-driven two-phase flows in capillary tube and porous medium
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High-order adaptive arbitrary-Lagrangian–Eulerian (ALE) simulations of solidification
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Multiscale-optimized plasma turbulence simulation on petascale architectures
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Output-based adaptive aerodynamic simulations using convolutional neural networks
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A generic implementation of replica exchange with solute tempering (REST2) algorithm in NAMD for complex biophysical simulations
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Oxidative dehydrogenation of ethane under a cyclic redox scheme – Process simulations and analysis
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Dissolved organic matter reduces CuO nanoparticle toxicity to duckweed in simulated natural systems
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Methodological factors influencing inhalation bioaccessibility of metal(loid)s in PM2.5 using simulated lung fluid
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Molecular dynamics simulations of zinc oxide solubility: From bulk down to nanoparticles
The solubility of metal oxides is one of the key descriptors for the evaluation of their potential toxic effects, both in the bulk form and in nanoparticulated aggregates. Current work presents a new methodology for the in silico assessment of the solubility of metal oxides, which is demonstrated using a well-studied system, ZnO. The calculation of the solubility is based on statistical thermodynamics tools combined with Density Functional Tight Binding theory for the evaluation of the free energy exchange during the dissolution process. Models of small ZnO clusters are used for describing the final dissolved material, since the complete ionic dissolution of ZnO is hindered by the formation of O2- anions in solution, which are highly unstable. Results show very good agreement between the computed solubility values and experimental data for ZnO bulk, up to 0.5 mg·L-1 and equivalents of 50 g·L-1 for the free Zn2+ cation in solution. However, the reference model for solid nanoparticles formed by free space nanoparticles can only give a limited quantitative solubility evaluation for ZnO nanoparticles.
Effects of calcium in ash on the corrosion performance of Ni-based alloys in simulated oxy-fuel environment
Increasing the efficiency of coal power plants requires raising the operating temperature above 650°C. However, coal ash can severely attack alloy materials at high temperature. For example, the corrosion rates of commercial Fe- and Ni-based alloys are generally greater than 2 mm/year at 750°C in the gas environment of oxy-fuel combustion. Thus, a critical study is needed to determine the effect of the constituents in the ash on corrosion and find an approach to reduce the corrosion rates in an ash-laden environment at high temperature. The role of CaO in the ash (typical of U.S. Western coal ash) has been investigated in laboratory exposure environments with various structural alloys. Detailed results are presented on weight change, scale thickness, internal penetration, microstructural characteristics of corrosion products, and the cracking of scales for the alloys after exposure at 750°C. The thermal stability of K3Al(SO4)3 under the environment of oxy-fuel combustion was determined by thermogravimetric analysis and differential thermal analysis. The reaction of this low melting temperature salt with the CaO-containing ash is discussed. In addition, we performed synchrotron nanobeam X-ray analysis to study the phase and chemical composition of the oxide layers on the alloy surface. Results from these studies are used to address the role of CaO in ash in the long-term corrosion performance of alloys.