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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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A comparison of shockwave dynamics in stochastic and periodic porous polymer architectures
Abstract not provided
Promoting Transport Kinetics in Li-Ion Battery with Aligned Porous Electrode Architectures
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A Distinct MaoC-like Enoyl-CoA Hydratase Architecture Mediates Cholesterol Catabolism in Mycobacterium tuberculosis
Abstract not provided
Architecture of the synaptotagmin–SNARE machinery for neuronal exocytosis
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A nanostructured cathode architecture for low charge overpotential in lithium-oxygen batteries
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Accurate and scalable graph neural network force field and molecular dynamics with direct force architecture
Abstract Recently, machine learning (ML) has been used to address the computational cost that has been limiting ab initio molecular dynamics (AIMD). Here, we present GNNFF, a graph neural network framework to directly predict atomic forces from automatically extracted features of the local atomic environment that are translationally-invariant, but rotationally-covariant to the coordinate of the atoms. We demonstrate that GNNFF not only achieves high performance in terms of force prediction accuracy and computational speed on various materials systems, but also accurately predicts the forces of a large MD system after being trained on forces obtained from a smaller system. Finally, we use our framework to perform an MD simulation of Li 7 P 3 S 11 , a superionic conductor, and show that resulting Li diffusion coefficient is within 14% of that obtained directly from AIMD. The high performance exhibited by GNNFF can be easily generalized to study atomistic level dynamics of other material systems.
Controlling shockwave dynamics using architecture in periodic porous materials
Additive manufacturing (AM) is an attractive approach for the design and fabrication of structures capable of achieving controlled mechanical response of the underlying deformation mechanisms. While there are numerous examples illustrating how the quasi-static mechanical responses of polymer foams have been tailored by additive manufacturing, there is limited understanding of the response of these materials under shockwave compression. Dynamic compression experiments coupled with time-resolved X-ray imaging were performed to obtain insights into the in situ evolution of shockwave coupling to porous, periodic polymer foams. We further demonstrate shock wave modulation or “spatially graded-flow” in shock-driven experiments via the spatial control of layer symmetries afforded by additive manufacturing techniques at the micron scale.
Architecture-based multiscale computational modeling of plant cell wall mechanics to examine the hydrogen-bonding hypothesis of cell wall network structure model
A primary plant cell wall network was computationally modeled using the finite element approach to study the hypothesis of hemicellulose (HC) tethering with the cellulose microfibrils (CMFs) as one of the major load-bearing mechanisms of the growing cell wall. A computational primary cell wall network fragment (10 × 10 μm) comprising typical compositions and properties of CMFs and HC was modeled with well-aligned CMFs. The tethering of HC to CMFs is modeled in accordance with the strength of the hydrogen bonding by implementing a specific load-bearing connection (i.e. the joint element). The introduction of the CMF-HC interaction to the computational cell wall network model is a key to the quantitative examination of the mechanical consequences of cell wall structure models, including the tethering HC model. When the cell wall network models with and without joint elements were compared, the hydrogen bond exhibited a significant contribution to the overall stiffness of the cell wall network fragment. When the cell wall network model was stretched 1% in the transverse direction, the tethering of CMF-HC via hydrogen bonds was not strong enough to maintain its integrity. When the cell wall network model was stretched 1% in the longitudinal direction, the tethering provided comparable strength to maintain its integrity. This substantial anisotropy suggests that the HC tethering with hydrogen bonds alone does not manifest sufficient energy to maintain the integrity of the cell wall during its growth (i.e. other mechanisms are present to ensure the cell wall shape).
Minerva: Rethinking Secure Architectures for the Era of Fabric-Attached Memory Architectures.
Abstract not provided.
Architecture for Hard Disk Drives
Magnetic data storage has made rapid progress in terms of areal density over the past few decades. Current products have areal density levels that exceed 10(12) bits per square inch, about 1000 times greater than areal densities of the mid-1990s. Five component technologies have become hard-disk-drive industry standards over the past two decades: read heads based on giant magnetoresistance or tunneling magnetoresistance, perpendicular write heads, perpendicular recording media, heaters, and contact detection sensors. At the recording system level, shingled magnetic recording has been implemented by all disk-drive companies, but it has not become a new standard due to the additional penalty in access time (or latency). Here, interlaced magnetic recording and blocked magnetic recording are introduced and compared with conventional and shingled magnetic recording.
A Resurgence in Neuromorphic Architectures Enabling Remote Sensing Computation.
Abstract not provided.
DC Grid Interface for the Integrated Generator–Rectifier Architecture in Wind Energy Systems
Not provided.