Mobility and aggregation of oxygen inYBa2Cu3O6+xin the low-concentration limit

1994 ◽  
Vol 50 (22) ◽  
pp. 16679-16683 ◽  
Author(s):  
G. Cannelli ◽  
R. Cantelli ◽  
F. Cordero ◽  
N. Piraccini ◽  
F. Trequattrini ◽  
...  
Keyword(s):  
Concentration Limit ◽  
Low Concentration

LOW CONCENTRATION LIMIT FOR A FLUID FLOW THROUGH A FILTER

1998 ◽  
Vol 08 (04) ◽  
pp. 623-643 ◽  
Author(s):  
SANJA MARUŠIĆ
Keyword(s):  
Asymptotic Behavior ◽  
Fluid Flow ◽  
Volume Fraction ◽  
Periodic Array ◽  
Concentration Limit ◽  
Global Flow ◽  
Low Concentration ◽  
Flow Through ◽  
Low Volume ◽  
Filtration Law

A fluid flow through an ∊-periodic array of obstacles distributed on a hypersurface (filter) is considered. The study of the asymptotic behavior as ∊→0 for two critical sizes of obstacles ∊ and ∊2 gives two different laws describing a global flow. In this paper we study the case of an intermediate obstacle size ∊β, 1 < β < 2 and we prove the continuity of the filtration law in the low-volume fraction limit.

scholarly journals Effects of Re on Vacancy Mobility in a Ni-Re System: An Atomistic Study

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Nuttapong La-ongtup ◽  
Suttipong Wannapaiboon ◽  
Piyanut Pinyou ◽  
Worawat Wattanathana ◽  
Yuranan Hanlumyuang
Keyword(s):  
Kinetic Monte Carlo ◽  
Saddle Points ◽  
Initial Energy ◽  
Concentration Limit ◽  
Low Concentration ◽  
Embedded Atom ◽  
Atomistic Calculations ◽  
The Difference ◽  
And Migration ◽  
Atomistic Study

The performance of modern Ni-based superalloys depends critically on the kinetic transport of point defects around solutes such as rhenium. Here, we use atomistic calculations to study the diffusion of vacancy in the low-concentration limit, using the crystalline fcc-framework nickel as a model. On-the-fly kinetic Monte Carlo is combined with an efficient energy-valley search to find energies of saddle points, based on energetics from the embedded atom method. With this technique, we compute the local energy barriers to vacancy hopping, tracer diffusivities, and migration energies of the low-concentration limit of Ni-Re alloys. It was estimated that the computed diffusion rates are comparable to the reported rates. The presence of Re atoms affects the difference between the energy of the saddle point and the initial energy of point defect hopping. In pure Ni, this difference is about 1 eV, while at 9.66 mol% Re, the value is raised to about 1.5 eV. The vacancy migration energy of vacancy in the 9.66 mol % Re sample is raised above that of pure Ni. Our findings demonstrate that even in the low-concentration limit, Re solute atoms continue to play a crucial role in the mobility of the vacancies.

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