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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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Coefficient datasets for high-order, stable, and conservative boundary schemes for central and compact finite differences
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Significant life extension of lithium-ion batteries using compact metallic lithium reservoir with passive control
Both traditional graphite-based lithium-ion batteries and next generation silicon-based chemistries suffer significant capacity fade from loss of cyclable lithium due to continued solid-electrolyte interphase growth. A possible engineering solution to maintaining the capacity of cells is incorporating a metallic lithium reservoir and discharging the reservoir into a working electrode to make up for lost cyclable lithium. Here, metallic lithium reservoirs are inserted into both pouch- and cylindrical-format cells. Significant capacity recovery and lifetime extension are demonstrated for traditional graphite and Si/graphite-based cells. In this work, a combination of post-mortem characterization and modeling provide insight into how the lithium distribution as a function of position from reservoir vary with recovery rate. The potential of using passive control to potentially eliminate the need for extra wiring for the third electrode is explored using a simple resistor.
A scoping study of far-SOL main-wall protection limiters for steady-state operation of compact pilot plant tokamaks
We present a novel method for handling steady-state heat fluxes incident on the main wall of pilot plant-scale magnetic fusion devices, based on the utilization of protection limiters in the far scrape-off layer (SOL). This method helps avoid large plasma-wall gaps, without excessively compromising blanket performance. We present an optimization algorithm for determining the appropriate size and scale of these protection limiters given (1) probability distributions of SOL plasma parameters and (2) assumed risk tolerance. As part of this optimization, we have developed an analytic description of parallel heat fluxes across limiter shadows, and an objective cost function (the ‘Far-SOL Marginal Cost’) to quantify the impact that different main-wall thermal management design choices have on reactor capital cost. Applying the model to a midscale fusion pilot plant concept shows that making use of far-SOL protection limiters can reduce capital costs on the order of $500 M, relative to naively increasing the plasma-wall gap. Our analysis demonstrates that the far-SOL power decay length is the highest-leverage plasma assumption for thermal loading of the first wall, and the primary cost driver for main wall thermal management. The relative cost efficiency of protection limiters increases as assumptions on the far-SOL heat flux become more pessimistic. The concepts described in this paper motivate the further development of far-SOL protection limiters as part of larger efforts to design economical core-edge-wall compatible solutions for a fusion pilot plant.
Discrete Dilatant Pathway Modeling of Gas Migration Through Compacted Bentonite Clay
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Modelling advective gas flow in compact bentonite: Lessons learnt from different numerical approaches
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A porosity-based model of dynamic compaction in under-dense materials
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The strand exchange domain of tumor suppressor PALB2 is intrinsically disordered and promotes oligomerization-dependent DNA compaction
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The compact gradient recovery discontinuous Galerkin method for diffusion problems
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On rapid compaction of granular materials: Combining experiments with in-situ imaging and mesoscale modeling
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Quantifying 3D time-resolved kinematics and kinetics during rapid granular compaction, Part I: Quasistatic and dynamic deformation regimes
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Quantifying 3D time-resolved kinematics and kinetics during rapid granular compaction, Part II: Dynamics of heterogeneous pore collapse
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X-ray computed tomography of deconsolidated TRISO Particles from the AGR-5/6/7 irradiation experiment capsule 1 Compact
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Compact ammonia reforming at low temperature using catalytic membrane reactors
Ammonia is a leading carrier for the storage and transport of renewable hydrogen, but its deployment requires scalable technologies for efficient decomposition and purification. In this work, we report on the efficient delivery of high purity hydrogen from ammonia decomposition using a catalytic membrane reactor (CMR). Improvements to the electroless plating process reduced the Pd membrane thickness by >35%, resulting in commensurate increases in hydrogen permeance without sacrificing selectivity. To increase throughput a commercial Ru/Al 2 O 3 catalyst was added to the lumen, and the CMR could process ammonia flowrates 10–50 times higher than an equivalent packed bed reactor while maintaining the same level of conversion. It is shown that the earth-abundant zeolite clinoptilolite could reduce ammonia impurities in the permeated H 2 to the levels required by PEM fuel cells (<25 ppb). Performance increased significantly across a >500-h durability test due to improvements in membrane permeability. Finally, the results show that CMRs are a viable technology for distributed production of hydrogen from ammonia.