The Use of Yttrium for the Recovery of Tritium from Lithium at Low Concentrations

Buxbaum, Robert E.; Johnson, Ernest F.

doi:10.13182/nt80-a32492

Cited by 22 publications

(11 citation statements)

References 11 publications

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note that peak shear stresses (overshoots) increase with increasing time of recovery. diffusion-limited process (27). Since reaction-limited models are linear with time in the short time limit, reaction-limited models should not produce a reasonable fit to the stressovershoot data.…”

Section: Resultsmentioning

confidence: 99%

Liquid crystal domains and thixotropy of filamentous actin suspensions.

Kerst

Chmielewski

Livesay

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The thixotropic properties of filamentous actin suspensions were examined by a step-function shearing protocol. Samples of purified framentous actin were sheared at 0.2 sec' in a cone and plate rheometer. We noted a sharp stress overshoot upon the initiation of shear, indicative of a gel state, and a nearly instantaneous drop to zero stress upon cessation of shear. Stress-overshoot recovery was almost complete after 5 min of "rest" before samples were again sheared at 0.2 sec1.Overshoot recovery increased linearly with the square root of rest time, suggesting that gel-state recovery is diffusion limited. Actin suspensions subjected to oscillatory shearing at frequencies from 0.003 to 30 radians/sec confirmed the existence of a 5-min time scale in the gel, similar to that for stress-overshoot recovery. Flow of filamentous actin was visualized by polarized light observations. Actin from 6 mg/ml to 20 mg/ml showed the "polycrystalline" texture of birefringence typical for liquid crystal structure. At shear rates <1 sec', flow occurred by the relative movement of irregular, roughly ellipsoidal actin domains 40-140 ,um long; the appearance was similar to moving ice floes. At shear rates >1 sect, domains decreased in size, possibly by frictional interactions among domains. Eventually domains flow in a "river" of actin aligned by the flow. Our observations confirm our previous domain-friction model for actin rheology. The similarities between the unusual flow properties of actin and cytoplasm argue that cytoplasm also may flow as domains.Cytoplasm and suspensions of actin have unusual and complex fluid behaviors that must play a role in such phenomena as cytoplasmic streaming, amoeboid movement, movement of vesicles through the cytoplasm, and bulk flow of polymer. Both cytoplasm and actin solutions are shear thinning; their viscosity decreases with increasing shear rate (1-8). Shear thinning of actin differs from most polymer solutions in the absence of a Newtonian viscosity plateau at very low shear rates (1-4, 7). Further, cytoplasm and cytoskeletal suspensions show a constant shear stress (force) for shear rates between 0.001 and 1 sect (1, 5). Flow rate, therefore, is not fixed by the force; no flow occurs at forces less than the constant and fluid velocity is limited by inertia alone at forces higher than the constant. We (1) called this "flow indeterminacy," which, for example, helps explain the capacity of Physarum to support very rapid cytoplasmic streaming within "walls" of cytoplasm that do not shear away: High flow rates do not necessarily require large forces and a small difference in filament concentration could account for the difference between flowing and nonflowing cytoplasm. Cytoplasm and actin suspensions are also thixotropic (3, 4, 8-10)-i.e., show time-dependent decreases in viscosity at steady shear rate and subsequent recovery when the flow is discontinued (11). Thixotropy is frequently discussed in terms of gel --sol transitions familiar to biologists and has been among the most durable ...

show abstract

Section: Resultsmentioning

confidence: 99%

Liquid crystal domains and thixotropy of filamentous actin suspensions.

Kerst

Chmielewski

Livesay

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…hs demonstrated by Buxbaum and Johnson (1980), from many standpoints, the simplest and most attractive breeding medium is liquid lithium, and the most attractive tritium recovery medium is solid yttrium metal.…”

Section: Scopementioning

confidence: 99%

Diffusivity of hydrogen isotopes in liquid lithium and in solid yttrium

Buxbaum¹,

Johnson²

1985

Ind. Eng. Chem. Fund.

Self Cite

View full text Add to dashboard Cite

The separation of tritium from liquid lithium at low concentrations is an important problem for fusion technology. One of the most promising techniques for effecting this separation involves sorbing the tritium on solid yttrium metal. Reliable diffusivity data are essential for a realistic evaluation of this technique. This paper reviews the relevant experimental diffusivity data on protlum diffusion In liquid lithium, protium diffusion in solid yttrium, and the isotope

show abstract

“…The simplest explanation for this discrepancy is that surface resistance, the hydrogen recombination reaction, for example, reduced the apparent dif "usivity in the vacuum desorption experiments. This hypothesis, suggested by Buxbaum et_ al. (1980) and Talbot (1981), is supported by the recombination rate experiments of Jung (1973-4!…”

Section: The Diffusivity Of Hydrogen Isotopes In Yttriummentioning

confidence: 80%

Diffusivity of hydrogen isotopes in liquid lithium and in solid yttrium

Buxbaum¹,

Johnson²

1982

View full text Add to dashboard Cite

The separation of tritium from liquid lithium at low cono trations is an important problem for fusion technology. One of the most promis ng techniques for effecting this separation involves sorbing the tritium on solid yttrium metal. Reliable diffusivity data are essential for a realistic evaluation of this technique.This paper reviews the bodies of relevant experimental diffus ity data, i.e., data on protium diffusion in liquid lithium, protium diffusior in solid yttrium, and the isotope effect in metals. On the basis of these data and in the light of standard correlations, the following equations are proposed for the diffusivity of tritium in liquid lithium and in solid yttrium respectively: and log 1Q D T _ Li = -9.0 38 + 1.73 7 log 10 T -110/T cm /s, log 1Q D T _ y = -2.391 -2558/T. These equations show that the geometries of yttrium systems for tritium gettering in fusion reactors are of quite practicable dimensions.•Present address:

show abstract

The Use of Yttrium for the Recovery of Tritium from Lithium at Low Concentrations

Cited by 22 publications

References 11 publications

Liquid crystal domains and thixotropy of filamentous actin suspensions.

Liquid crystal domains and thixotropy of filamentous actin suspensions.

Diffusivity of hydrogen isotopes in liquid lithium and in solid yttrium

Diffusivity of hydrogen isotopes in liquid lithium and in solid yttrium

Contact Info

Product

Resources

About