Dry-Machining of Aerogel Foams, CH Foams, and Specially Engineered Foams Using Turn-Milling Techniques

Randolph, R. B.; Oertel, J. A.; Cárdenas, T.; Hamilton, Christopher E.; Schmidt, D. W.; Fierro, F.; Capelli, Deanna

doi:10.1080/15361055.2017.1356196

Cited by 15 publications

(6 citation statements)

References 8 publications

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“…The bulk density for all foams was measured to be 33.0 ± 0.5 mg cm −3 . The foams are machined into 860 μm-diameter spheres 43 and placed inside machined Rexolite step-jointed hemi-shell halves 42 , which were then glued and machined into 900 μm-diameter spheres, which were then coated with 3 μm of glow discharge polymer (GDP). This procedure produced capsules with average shell thicknesses ranging from 22.0 to 26.2 μm and shell thickness variances ranging from 0.5 to 8.7 μm.…”

Section: Methodsmentioning

confidence: 99%

“…This uncertainty is the maximum and minimum possible values calculated based on measurement uncertainties of foam densities, foam composition, fill pressure, and fill gas composition. Measurement errors are quantified in the Methods section and described in[42][43][44][63][64][65] . The red plus symbols indicate values that would have resulted from simulations if the reactants were in thermal equilibrium.…”

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confidence: 99%

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Observation of persistent species temperature separation in inertial confinement fusion mixtures

et al. 2020

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The injection and mixing of contaminant mass into the fuel in inertial confinement fusion (ICF) implosions is a primary factor preventing ignition. ICF experiments have recently achieved an alpha-heating regime, in which fusion self-heating is the dominant source of yield, by reducing the susceptibility of implosions to instabilities that inject this mass. We report the results of unique separated reactants implosion experiments studying pre-mixed contaminant as well as detailed high-resolution three-dimensional simulations that are in good agreement with experiments. At conditions relevant to mixing regions in high-yield implosions, we observe persistent chunks of contaminant that do not achieve thermal equilibrium with the fuel throughout the burn phase. The assumption of thermal equilibrium is made in nearly all computational ICF modeling and methods used to infer levels of contaminant from experiments. We estimate that these methods may underestimate the amount of contaminant by a factor of two or more.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Observation of persistent species temperature separation in inertial confinement fusion mixtures

et al. 2020

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“…After the sleeves and mandrels were glued together, the assembly was cured for several days at room temperature to prevent adhesive shrinkage 36 . Machining the foam sphere required a new dry machining method developed using turn milling 37 to avoid difficulties with wax fill (e.g., non-uniform shrinkage and incomplete removal of the wax 38 ).…”

Section: Target Machiningmentioning

confidence: 99%

Experimental quantification of the impact of heterogeneous mix on thermonuclear burn

Albright

Murphy

Douglas

et al. 2021

Preprint

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In inertial confinement fusion (ICF), deuterium-tritium (DT) fuel is brought to densities and temperatures where fusion ignition occurs. Mix of ablator material into the fuel may prevent ignition by diluting and cooling the fuel. MARBLE experiments at the National Ignition Facility (NIF) provide new insight into how mix affects thermonuclear burn. These experiments use laser-driven capsules containing deuterated plastic foam and tritium gas. Embedded within the foam are voids of known sizes and locations, which control the degree of heterogeneity of the fuel. Initially, the reactants are separated, with tritium concentrated in the voids and deuterium in the foam. During the implosion, mix occurs, leading to DT fusion reactions in the mixed region. Here we show that by measuring ratios of DT and deuterium-deuterium (DD) neutron yields for different macropore sizes and gas compositions, effects of mix heterogeneity on thermonuclear burn may be quantified and understood for the first time.

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“…Despite their low density, the materials may be handled, cut, wetted, and redried, and even machined into complex shapes while maintaining their structural integrity. The latter was performed using novel dry aerogel machining techniques recently established for inertial confinement fusion and high energy density physics experiments at national laser facilities such as the National Ignition Facility and OMEGA . To demonstrate the high degree of mechanical strength of our materials, a spherical capsule of a carbon aerobijel was successfully machined with a remarkable tolerance of just 5 µm (see the Supporting Information).The walls of the aerogel are separated by uniform interpenetrating macroporous channels (formerly the liquid phases of the bijel), and the monolayer of carbon particles comprising the walls are completely hollow macroporous shells, affording high active surface areas up to ≈600 m 2 g −1 without activation.…”

Section: Deriving Aerogels From Bijel Scaffoldsmentioning

confidence: 99%

Aerobijels: Ultralight Carbon Monoliths from Cocontinuous Emulsions

Cordoba

Spendelow

Parra-Vasquez

et al. 2019

Adv Funct Materials

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Bijels are used to develop a new class of ultralight hierarchically porous aerogels exhibiting multimodal porosity across multiple length scales. Through in situ functionalization of a particle-laden liquid interface wherein binary liquid pairs are kinetically trapped out of equilibrium through interfacial jamming, monolithic and freestanding carbon electrodes are produced with prescribed bulk densities down to ≈2 mg cm −3 . Exemplary electrokinetic experiments indicate that the bicontinuity of the pore structure is essential for enhancing transport to and from the active electrode surfaces, demonstrating that these materials possess a superior ability to accumulate and transport charge when compared to analogous systems with restricted pore connectivity and fluid throughput. This approach offers a new synthetic route to bicontinuous and hierarchical aerogel materials with nested multimodal porosities. The flexibility of this scheme can address critical issues related to transport-limited behaviors that arise in many technological fields, ranging from energy and catalysis research to remediation and sensing applications.

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Dry-Machining of Aerogel Foams, CH Foams, and Specially Engineered Foams Using Turn-Milling Techniques

Cited by 15 publications

References 8 publications

Observation of persistent species temperature separation in inertial confinement fusion mixtures

Observation of persistent species temperature separation in inertial confinement fusion mixtures

Experimental quantification of the impact of heterogeneous mix on thermonuclear burn

Aerobijels: Ultralight Carbon Monoliths from Cocontinuous Emulsions

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