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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 novel nano-particle strengthened titanium alloy with exceptional specific strength
Various ecological and economical concerns have spurred mankind’s quest for materials that can provide enhanced weight savings and improved fuel efficiency. As part of this pursuit, we have microstructurally tailored an exceptionally high-strength titanium alloy, Ti-6Al-2Sn-4Zr-6Mo (Ti6246) through friction stir processing (FSP). FSP has altered the as-received bimodal microstructure into a unique modulated microstructure comprised of fine acicular α"-laths with nano precipitates within the laths. The sequence of phase transformations responsible for the modulated microstructure and consequently for the strength is discussed with the help of scanning electron microscopy, transmission electron microscopy, and synchrotron X-ray diffraction studies. The specific strength attained in one of the conditions is close to 450 MPa m 3 /mg, which is about 22% to 85% greater than any commercially available metallic material. Therefore, our novel nano particle strengthened Ti alloy is a potential replacement for many structural alloys, enabling significant weight reduction opportunities.
Enabling URR Self Shielding Functionality in SAMMY [Slides]
This lecture is on enabling Unresolved Resonance Energy Range (URR) self-shielding functionality in SAMMY. This presentation covers Fiscal Year 2022 milestones, and motivations driving this endeavor. This presentation includes slides depicting the current self-shielding correction workflow. Additionally, this presentation includes a look into the doppler broadening issue and the verification of capture. This lecture concludes with envisioned future work.
Recent Developments in the R-Matrix Code SAMMY [Slides]
Abstract not provided.
Fellowship of the Resolved [Slides]
There are new evaluation methods being explored for combined RRR + URR. Simple example demonstrated in SAMMY code using. Potential to be applied to future LoFi, Medium-Fi covariance efforts. Much more work needs to be done to fully correlate regions.
Effects of partitioning and scheduling sparse matrix factorization on communication and load balance
A block based, automatic partitioning and scheduling methodology is presented for sparse matrix factorization on distributed memory systems. Using experimental results, this technique is analyzed for communication and load imbalance overhead. To study the performance effects, these overheads were compared with those obtained from a straightforward 'wrap mapped' column assignment scheme. All experimental results were obtained using test sparse matrices from the Harwell-Boeing data set. The results show that there is a communication and load balance tradeoff. The block based method results in lower communication cost whereas the wrap mapped scheme gives better load balance.