Pressure relaxation and diffusion of vacancies in rapidly grown helium crystals

2018 ◽  
Vol 44 (4) ◽  
pp. 304-316 ◽  
Author(s):  
A. P. Birchenko ◽  
N. P. Mikhin ◽  
E. Ya. Rudavskii ◽  
S. N. Smirnov ◽  
Ya. Yu. Fysun
Keyword(s):  
Pressure Relaxation ◽  
Helium Crystals ◽  
And Diffusion ◽  
Diffusion Of Vacancies

Novel features of pressure relaxation in nonequilibrium helium crystals

2018 ◽  
Vol 44 (9) ◽  
pp. 938-945
Author(s):  
A. P. Bisrchenko ◽  
N. P. Mikhin ◽  
E. Ya. Rudavskii ◽  
S. N. Smirnov ◽  
Ya. Yu. Fysun
Keyword(s):  
Pressure Relaxation ◽  
Helium Crystals

Analysis of Internal Friction Peaks in High Purity Molybdenum by a Viscoelastic Procedure Independent of the Relaxation Strength

2008 ◽  
Vol 137 ◽  
pp. 49-58
Author(s):  
C.L. Matteo ◽  
O.A. Lambri ◽  
G.I. Zelada-Lambri ◽  
P.A. Sorichetti ◽  
Jose Angel García
Keyword(s):  
Internal Friction ◽  
High Purity ◽  
The Other ◽  
Relaxation Processes ◽  
Relaxation Strength ◽  
Viscoelastic Analysis ◽  
Linear Viscoelastic ◽  
Damping Peak ◽  
And Diffusion ◽  
Diffusion Of Vacancies

In this work we present a novel procedure, involving linear viscoelastic analysis, to discriminate the two possible contributions of the observed damping peak which appears around 840 K – 1050 K in mechanically deformed high purity single-crystalline molybdenum. An interesting feature of the procedure is that, for low damping samples, it can efficiently resolve experimental peaks that result from the superposition of different processes independently of the ratio between their relaxation strengths. This allows us to confirm that two different relaxation processes appear in molybdenum in the temperature range about 0.3 Tm, one around 840 K, and the other one near 1050 K. These can be related to diffusion and to a coupled mechanism involving creation and diffusion of vacancies, respectively.

Meridional Circulation, Turbulence, and Diffusion Processes in Stars

1976 ◽  
Vol 32 ◽  
pp. 109-116 ◽  
Author(s):  
S. Vauclair
Keyword(s):  
Convection Zone ◽  
Diffusion Processes ◽  
Meridional Circulation ◽  
Diffusion Time ◽  
Work In Progress ◽  
First Results ◽  
Stellar Envelopes ◽  
And Diffusion ◽  
Turbulence And Diffusion ◽  
Hr Diagram

This paper gives the first results of a work in progress, in collaboration with G. Michaud and G. Vauclair. It is a first attempt to compute the effects of meridional circulation and turbulence on diffusion processes in stellar envelopes. Computations have been made for a 2 Mʘstar, which lies in the Am - δ Scuti region of the HR diagram.Let us recall that in Am stars diffusion cannot occur between the two outer convection zones, contrary to what was assumed by Watson (1970, 1971) and Smith (1971), since they are linked by overshooting (Latour, 1972; Toomre et al., 1975). But diffusion may occur at the bottom of the second convection zone. According to Vauclair et al. (1974), the second convection zone, due to He II ionization, disappears after a time equal to the helium diffusion time, and then diffusion may happen at the bottom of the first convection zone, so that the arguments by Watson and Smith are preserved.

Ordering and diffusion in II-VI/III-VI alloys with structural vacancies

1997 ◽  
Vol 101-103 (1-2) ◽  
pp. 479-487
Author(s):  
H v. Wensierski
Keyword(s):  
And Diffusion
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