Mechanical response of stainless steel subjected to biaxial load path changes: Cruciform experiments and multi-scale modeling
Not Available
36 MATERIALS SCIENCE↗
SEARCH · Search NASA
Results for “Path”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Investigation of phase-transformation path in TiZrHf(VNbTa)x refractory high-entropy alloys and its effect on mechanical property
Refractory high-entropy alloys (RHEAs) show a great potential as structural materials due to their remarkable properties, such as high strength and thermal stability. Despite these advantages, the RHEAs still suffer from the limited ductility at room temperature. To overcome the strength-ductility trade-off, the new RHEA design strategy, transformation-induced plasticity (TRIP) HEAs, have been developed by applying metastability-engineering approach. With the newly developed RHEAs design strategy, we designed metastable RHEAs, TiZrHfVxNbxTax (x = 1.0, 0.5 and 0.1) with decrease of the β-stabilizing elements (V, Nb, and Ta) to promote the transformation-induced ductility and work-hardening capability. The proper addition of the β-stabilizing elements (V, Nb, and Ta) into the ternary equi-molar TiZrHf alloy (TiZrHfV 0.1 Nb 0.1 Ta 0.1 ) leads to stress/strain-induced phase transformation from the body-centered cubic (BCC) to hexagonal-close-packed (HCP) α' and/or orthorhombic α" phases. Here, detailed studies on the phase transformation sequence during the deformation were carried out using X-ray diffraction (XRD), electron back-scattered diffraction (EBSD), and transmission-electron microscope (TEM), which revealed the stepwise phase transformation that is responsible for the strong strain hardening behavior. Furthermore, we further suggested the new transformation-induced-plasticity (TRIP) HEA design strategy, applying the Bo-Md approach.
36 MATERIALS SCIENCE↗
Reaction paths of methane activation and oxidation of surface intermediates over NiO on Ceria-Zirconia catalysts studied by In-situ FTIR spectroscopy
Methane activation over NiO/Ce 0.82 Zr 0.18 O 2 catalysts synthesized by combustion synthesis is studied by in-situ IR spectroscopy and correlated to the properties and oxygen speciation of the catalyst. Through XRD, H 2 -TPR, and pyridine adsorption followed by FTIR spectroscopy, the reducibility and Lewis acidity of the catalysts are assessed. In-situ FTIR spectroscopy is used to monitor the methane activation on catalyst surfaces. Complex IR features of methane-derived surface species are observed and are attributed to the formation of surface alkyl/alkoxy, aldehyde, formate/carbonate, and aromatic species. A data analysis algorithm is developed to evaluate the evolution of different surface species over time. The formation of formate and carbonate species is driven by adsorbed surface oxygen, while less reactive oxygen species associated with NiO allow for the production of aromatics and alkoxy intermediates. Finally, by tuning the reducibility and Lewis acidity of the catalyst, the selectivity to alkoxy intermediates can be improved.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Reactive CO2 capture: A path forward for process integration in carbon management
Not Available
25 ENERGY STORAGE↗
A path toward cobalt-free lithium-ion cathodes
The necessity of developing low-cobalt cathode oxides for lithium-ion batteries is increasingly apparent. The most popular strategy followed thus far in addressing this issue has been the development of LiNiO 2 -like, Ni-rich, layered LiMO 2 (M = Ni, Mn, Co; NMC) oxides with low Mn and Co contents, e.g., NMC-811. However, safety, cycle-life, and even cost could remain critical barriers to the success of such cathode materials. Herein an alternative to LiNiO2-based, low-cobalt cathodes is suggested based on modifications to the prototypical cobalt-free, layered oxide, LiNi 0.5 Mn 0.5 O 2 .
25 ENERGY STORAGE↗
Ethanol internal reforming in solid oxide fuel cells: A path toward high performance metal-supported cells for vehicular applications
Internal reforming of ethanol fuel was explored on high-performance metal-supported solid oxide fuel cells (MS-SOFCs) with infiltrated catalysts. The hydrogen concentration and internal reforming effects were evaluated systematically with different fuels including: hydrogen, simulated reformate, anhydrous ethanol, ethanol water blend, and hydrogen-nitrogen mixtures. A simple infiltration of Ni reforming catalyst into 40 vol.% Ni-Sm 0.20 Ce 0.80 O 2-δ (Ni-SDCN 40 ) and fuel-side metal support leads to complete internal reforming, as validated by comparison to simulated reformate. The performance difference between hydrogen and fully-reformed ethanol is attributed entirely to decrease in hydrogen concentration. High peak power density was achieved for a range of conditions, for example 1.0 W cm -2 at 650 °C in ethanol-water blend, and 1.4 W cm -2 at 700 °C in anhydrous ethanol fuel. Initial durability tests with ethanol-water blend show promising stability for 100 hours at 700 °C and 0.7 V. Carbon is not deposited in the Ni-SDCN 40 anode during operation.
25 ENERGY STORAGE↗
Microstructural and micro-mechanical analysis of 14YWT nanostructured Ferritic alloy after varying thermo-mechanical processing paths into tubing
Microstructural analyses and micro-pillar compression were conducted on 14YWT nanostructured ferritic alloy (NFA) to compare different processing pathways: hydrostatic extrusion and Pilger processing with varying annealing temperatures into thin walled tubing, and after hot extrusion and cross-rolling into a plate. Hydrostatic extrusion at 815 °C resulted in the smallest grain sizes and highest yield strength of 1.20 GPa. Pilger processing with annealing at 800 °C had fine grained regions and bands of coarse grains, leading to a large variation in yield strength of 0.9–1.40 GPa. Higher annealing temperatures of 1200 °C after pilger processing significantly increased the grain size and lowered the yield strength to 1.01 GPa. These tubes showed a stronger (111) crystallographic texture in the normal direction and elongated grains in the extrusion direction. Characterization of the nano-oxides using TEM reveals more numerous, smaller oxides present in tubing processed at lower temperatures. Overall, this work shows NFA tubing after hydrostatic extrusion and pilger processing can lead to fine grained microstructures and texturing leading to higher yield strengths at lower annealing temperatures (e.g. 800 °C).
14YWT↗
Digital atomic scale fabrication an inverse Moore's Law – A path to atomically precise manufacturing
There is an exciting opportunity to start a second digital revolution that will supersede the first digital revolution in information technology (IT) as the primary driver of scientific, technological, and economic growth. This new revolution will be digital fabrication technology. Here, the digital IT revolution has been largely driven by digital algorithms such as error detection and correction and Moore's Law which has given us an exponential trend in product capabilities. However, the longstanding trend in improving manufacturing precision which has enabled Moore's Law simply cannot be continued much longer because we are running into the limits imposed by the quantized nature of matter. At this scale, matter can no longer be treated in an analogue fashion i.e. as an infinitely divisible medium, but must be treated as an integer number of discrete atomic distances, i.e. in a digital fashion. By embracing this digital nature of matter, we can conceive of a digital fabrication technology, where the digital processes are the making and breaking of chemical bonds, there is a digital address grid that is spatial in nature, and error detection and correction processes can be developed. This digital fabrication technology will have the similarly huge advantages over analog fabrication that digital IT has over analog IT. We remind the reader that effective digital technologies are not exclusively digital in their operation. Digital electronics is carried out by analog transistors that are embedded in circuitry designed to accept their output in a digital fashion. Digital fabrication technology is not synonymous with Atomically Precise Manufacturing (APM) but should lead to that important capability. Furthermore this digital fabrication technology will start a new exponential manufacturing trend that will replace Moore's law and will not be just for information processing and therefore will have an even larger impact than Moore's Law. Like any exponential trend Digital Fabrication will start slowly in a few niche markets, but the time for investing in the development of this new technology is now.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Second Messenger cA4 Formation within the Composite Csm1 Palm Pocket of Type III-A CRISPR-Cas Csm Complex and Its Release Path
Not Available
59 BASIC BIOLOGICAL SCIENCES↗
A muon–ion collider at BNL: The future QCD frontier and path to a new energy frontier of μ + μ – colliders
In this work, we propose the development and construction of a novel muon–ion collider (MuIC) at Brookhaven National Laboratory (BNL) in the USA as an upgrade to succeed the electron–ion collider (EIC) that is scheduled to commence in the early 2030s, by a joint effort of the nuclear and particle physics communities. The BNL facility could accommodate a muon storage beam with an energy up to about 1 TeV with existing magnet technology. When collided with a 275 GeV hadron beam, the MuIC center-of-mass energy of about 1 TeV will extend the kinematic coverage of deep inelastic scattering physics at the EIC (with polarized beams) by more than an order of magnitude in Q 2 and x, opening a new QCD frontier to address many fundamental scientific questions in nuclear and particle physics. This coverage is comparable to that of the proposed Large Hadron–Electron Collider (LHeC) at CERN, but with complementary lepton and hadron kinematics, ion species, and beam polarization. Additionally, the development of a MuIC at BNL will focus the worldwide R&D efforts on muon collider technology and serve as a demonstrator toward a future muon–antimuon collider at O(10) TeV energy, which is an attractive option to reach the next high energy frontier in particle physics at an affordable cost and a smaller footprint than a future circular hadron collider. We discuss here the possible design parameters of the MuIC, kinematic coverage, science cases, and detector design considerations including resolution estimates on DIS kinematic variables. A possible road map toward the future MuIC and muon–antimuon colliders is also presented.
43 PARTICLE ACCELERATORS↗
Adaptive path following control for Wave gliders in time-varying environment
Not Available
Sun, Xiujun↗
Paths to circularity for plastics in the United States
In 2019, the United States consumed over 57 million metric tons (MMT) of plastic with less than 7% recovered for reuse. This study provides an updated material flow analysis at national and regional scales for all durable and single-use plastics in the United States. From this material flow analysis, we develop a series of alternative future national plastic flow scenarios that envision a scale-up of recycling technologies, incorporating technical limitations and sorting infrastructure constraints. The results suggest that a maximum of 68% (24 MMT) of plastic waste could be diverted from landfills by scaling up existing commercial recycling technologies. Based on the current technological landscape, reaching near-zero waste is only possible if processes that are operating at pilot and laboratory scales can be effectively scaled and coupled with improved sorting infrastructure. Through these scenarios with increased recycling, the availability of postconsumer resin stocks could increase by 22–43 MMT.
36 MATERIALS SCIENCE↗