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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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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Response to comment on “Giant electromechanical coupling of relaxor ferroelectrics controlled by polar nanoregion vibrations”

Gehring et al . argue that a splitting observed by us in the transverse acoustic (TA) phonon in the relaxor ferroelectric Pb[(Mg 1/3 Nb 2/3 ) 1- x Ti x ]O 3 with x = 0.30 (PMN-30PT) is caused by a combination of inelastic-elastic multiple scattering processes called ghostons. Their argument is motivated by differences observed between their measurements made on a triple-axis spectrometer and our measurements on a time-of-flight spectrometer. We show that the differences can be explained by differences in the instrument resolution functions. We demonstrate that the multiple scattering conditions proposed by Gehring et al . do not work for our scattering geometry. We also demonstrate that, when a ghoston is present, it is too weak to detect and therefore cannot explain the splitting. Finally, this phonon splitting is just one part of the argument, and the overall conclusion of the original paper is supported by other results.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Enhancing Lithium-Ion Battery Aging Simulations: Coupling a High-Resolution, 3D, Grain-Scale Electromechanical Model to a Single-Particle Model

One of the main goals in modeling lithium-ion batteries is to improve/predict longevity and resilience of new chemistries. Unfortunately, this requires simulation of thousands of charge/discharge cycles, which can be rather time consuming depending on the fidelity of the simulation. The purpose of this talk is to discuss a new modeling framework that couples a high-resolution, continuous damage model (CDM) to a single particle model (SPM) resulting in a good combination of speed and fidelity. In previous work, a 3D, continuum-level chemo-mechanical model was developed to investigate cracking within a single cathode particle comprised of hundreds to thousands of randomly oriented grains. The CDM predicted that particle fracture is primarily due to non-ideal grain interactions with slight dependence on high-rate charge demands. Essentially, when neighboring grains were misaligned, they expanded different rates relative to one another leading to high stresses and ultimately the formation of intraparticle cracks. The model predicted that small particles with large grains develop significantly less damage than larger particles with small grains. Finally, the model predicted most of the chemo-mechanical damage accumulates in the first charge after formation. This chemo-mechanical "damage saturation" effect indicated that initial particle fracture occurs within the first few cycles, while long-term cathode degradation is not solely chemo-mechanically induced. This led to a need for simulating fatigue-like mechanism that degrade the battery over longer time scales. In order to reach the time scales, need to resolve fatigue-like degradation, the CDM needs to be complemented by a faster model. Therefore, recent efforts have been focused on using results from the CDM to inform parameters within the SPM. These parameters are homogenization factors that are associated with diffusion, particle radius, and/or exchange current density. By coupling the CDM to the SPM, the aging simulation is broken up into two domains: short-term and long-term degradation. The short-term degradation occurs over a single cycle and is handled by the CDM due of its high fidelity, but relatively expensive computational cost. Such mechanism include break-in crack caused by mismatches in grain orientation. The long-term degradation occurs over tens of cycles and is handled by the SPM due it's computational efficiency. Most of the fatigue-like mechanism fall into this category. The eventual goal of this modeling framework is to upscale to a psudo-2D model allowing for full electrode simulation, which are informed by high-fidelity grain-scale simulations.

electrochemistry↗
DOE OSTI2013

Utility-Scale Electromechanical Battery (EMB) for Modules of 200kWhr or More, CRADA No. TC02151.0

This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and EMB Energy, Inc. (EMB Energy), to develop a utility-scale electro-mechanical battery (EMB) to facilitate bulk-energy storage. The technical objectives of this CRADA project were to design, fabricate and test an EMB capable of storing between 200-250 kWh of electrical energy without significant losses for up to 96 hours at a projected cost of $420 per kWh (installed), or less. The results of this CRADA would provide the information required to design a final full-scale demonstration unit (200-250 kWh) to support the finalization of engineering and manufacturing plans.

25 ENERGY STORAGE↗
DOE OSTI2016

Vertical Testing of Eco-Friendly Bipolar Electromechanical Bulk Processing of SRF Cavities

Fermilab will provide a single-cell 1.3 GHz RF cavity and niobium coupons for Faraday Technology to use to develop the bulk bi-polar electropolishing process. The RF cavity will remain Fermilab property. Phase I will first demonstrate the feasibility of the process on coupons to optimize Bipolar EP process parameters to achieve niobium removal rates that are compatible with bulk processing throughput rates, while maintaining desired surface finishes. Subsequently in Phase I, we will transition the Bipolar EP process from coupons to bulk processing of single-cell cavities, while maintaining the desired removal rates. The project team will determine the performance effect of the Bipolar EP Bulk Process via cavity testing, and develop a preliminary economic analysis showing the commercial viability of the technology as compared to conventional practice. Under this CRADA, Fermilab provided a 1.3 GHz RF cavity to Faraday Technology to use for acid-free electropolishing studies. The original scope of work provided for up to two tests of the electropolished cavity in Fermilab’s Vertical Test Stand (VTS).

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Thermal and electromechanical response of ultra-thin carbon-strip polarimeter targets in relativistic bunched beams

Thin carbon-strip targets provide fast relative hadron beam polarimetry, but their response in intense relativistic bunched beams is not governed by local stopping-power heating alone. We develop a coupled response model that combines beam-target overlap, secondary-electron escape, retained heat, target motion, transient heat transport, RF-induced strip-end heating, beam-induced forces, resistance changes, and slack-strip deformation. RHIC target observations constrain the relevant motion, force, and nonlocal-heating scales and show that target survival depends on both beam-center heating and electromagnetic boundary conditions near the strip ends. Applying the model to Booster, AGS, RHIC, and EIC proton and 3 He cases shows that the RHIC proton lifetime scale is reproduced at the order-of-magnitude level, while the RHIC target-holder fin results require the additional RF/end-heating mechanism. For EIC proton flattop operation, carbon-strip polarimetry may remain viable only with reduced dwell time, sufficient detector acceptance, and suppression of RF-induced end heating. For cooled-emittance 3 He, the calculated sublimation-loss scale is far beyond a straightforward RHIC-like carbon-strip extrapolation. Conventional carbon strips are therefore unlikely to remain viable for the most demanding EIC light-ion cases without major changes in target motion, target technology, or diagnostic concept.

43 PARTICLE ACCELERATORS↗
NASA NTRS1968

Improved electromechanical master-slave manipulator

Electric master-slave manipulator uses force multiplication and allows the operator to remotely control the slave arm. Both the master and slave arms execute seven distinct motions by a specially designed force-reflecting servo having a one to one correspondence between the motion at the master and slave.

Forster, G.↗
NASA NTRS1971

Long-life electromechanical sine-cosine generator

Sine-cosine generator with no sliding parts is capable of withstanding a 20 Hz oscillation for more than 14 hours. Tests show that generator is electrically equal to potentiometer and that it has excellent dynamic characteristics. Generator shows promise of higher-speed applications than was previously possible.

Flagge, B.↗
NASA NTRS1975

Reliability data for electronic and electromechanical components: A report

Ten classes of parts covered in report: capacitors, crystals, diodes, fuses, inductors, microcircuits, relays, fixed resistors, transformers, and transistors. Each class is contained in separate section and includes discussion of inherent failure modes, screening rationale, general screening requirements, derating criteria, and stress-analysis data.

Scott, W. R.↗