In-Situ NMR Study of Dislocation Jump Distance During Creep of Pure and Doped NACL Single Crystals

1988 ◽  
Vol 142 ◽  
Author(s):  
K. Linga Murty ◽  
O. Kanert
Keyword(s):  
Steady State ◽  
Single Crystals ◽  
Pulse Sequence ◽  
Subgrain Size ◽  
Steady State Creep ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Nmr Study ◽  
Jump Distance

AbstractNuclear magnetic resonance pulse techniques are used in-situ during creep of single crystals of NaCl to evaluate the contribution of mobile dislocations to spin relaxation. 23Na spin-lattice relaxation rates were measured in the rotating frame (T1ρ) during compression creep of single crystals of NaCl along [110] direction at 473K at an applied stress of 20 MPa. The relaxation rates are evaluated from the spin-echo height following π/2, locking and 67° pulse sequence. The height of the free induction decay decreased as soon as the load is applied followed by a gradual increase until the steady-state is reached, at which point a saturation value is observed corresponding to the constant steady-state creep-rate. The mean jump distance of the mobile dislocations, evaluated from the ratio of the signal heights without deformation and during creep, decreased with time/strain reaching a constant value during steady-state creep regime. The results are compared with the dislocation-dislocation spacing, subgrain size as well as the jump distance predicted from creep models. The effects of dilvalent Ca and solid solution with LiCl are examined.

In Situ NMR Study of Dislocation Jump Distance During Creep of Pure Sodium Chloride Single Crystals

1990 ◽  
Vol 73 (4) ◽  
pp. 861-865 ◽  
Author(s):  
K. Linga Murty ◽  
Dietmar Begert ◽  
Rolf Munter ◽  
Otmar Kanert
Keyword(s):  
Sodium Chloride ◽  
Single Crystals ◽  
Nmr Study ◽  
Jump Distance ◽  
In Situ Nmr

Reduction in steady-state creep rates by aluminum-doping in zinc single crystals

1982 ◽  
Vol 16 (5) ◽  
pp. 551-554 ◽  
Author(s):  
K. Maruyama ◽  
S. Karashima ◽  
H. Oikawa ◽  
T. Sato
Keyword(s):  
Steady State ◽  
Single Crystals ◽  
Steady State Creep ◽  
Aluminum Doping

Features of the subboundary structure in deformed molybdenum single crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 316-317
Author(s):  
M.M. Myshlyaev ◽  
I.I. Khodos ◽  
O.N. Senkov ◽  
Yu.A. Romanov
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Single Crystals ◽  
Dislocation Line ◽  
Regular Structure ◽  
Steady State Creep ◽  
Burgers Vector

The subboundary structure corresponding to the high temperature steady-state creep of molybdenum single crystals is formed by both regular sites of dislocation nets and walls, various in structure and composition, (the nets are formed by two, three, five and six dislocation sets having different values of the angles between the Burgers vector Ḇ and the dislocation line ū ; the walls are formed by one, two and three sets of edge and mixed dislocations; the Burgers vectors of the dislocations are I/2 <III> and, <I00>) and by the sites of a more complex and less regular structure. Several of these are considered below.Fig.I represents a subboundary formed by five dislocation sets.Its regular sites (nets) can be formed by means of interaction of dislocations I and 4 with dislocations 2 (fig.2a). In several irregular sites (fig.I and 2b) no dislocations 2 are seen to be present, and neither dislocations 3 and 5 arisen from the reactions of dislocations 2 with dislocations I and 4.

NMR Study of the Molecular Motion of Water in Natrolite

1974 ◽  
Vol 52 (21) ◽  
pp. 2164-2173 ◽  
Author(s):  
R. T. Thompson ◽  
R. R. Knispel ◽  
H. E. Petch
Keyword(s):  
Molecular Motion ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Water Molecules ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Nmr Study ◽  
History Of ◽  
Made In

The dynamics of water molecules in natrolite (Na2Al2Si3O10∙2H2O) were studied using proton magnetic resonance. At 4.2 K, rigid lattice values were observed for the proton second moment and line width and these quantities changed little up to 400 K. Between 300 and 460 K a narrower component of the proton line appeared, the relative intensity of which depended on the thermal history of the sample. The narrower component grew rapidly at the expense of the broader component as the temperature was increased above 460 K until only a narrow line (δH < 1 G) remained at 545 K. Spin lattice relaxation time measurements were made in the laboratory (T1) and rotating (T1ρ) frames. T1 decreased monotonically from 20 s at 77 K to 0.2 s at 435 K but did not reach a relative minimum. Relative minima in T1ρ were observed at 280 and 377 K for H1 = 4 G and the activation energies for the processes responsible for these minima were determined to be 8.6 ± 0.6 and 13 ± 2 kcal/mole respectively. Spin lattice relaxation rates based on 180° flips and other possible motions of the water molecules are discussed and compared to results obtained in other hydrates and zeolites.

scholarly journals Observations of pressure effects on the creep of ice single crystals

1996 ◽  
Vol 42 (140) ◽  
pp. 169-175 ◽  
Author(s):  
David M. Cole
Keyword(s):  
Steady State ◽  
Creep Rate ◽  
Single Crystals ◽  
Basal Slip ◽  
Confining Pressure ◽  
Absolute Temperature ◽  
Steady State Creep ◽  
Pressure Effects ◽  
Steady State Creep Rate ◽  
Experimental Errors

AbstractExperiments performed on ice single crystals oriented for basal slip indicate that the steady-state creep rate is only marginally affected by confining pressure up to 19 MPa, at a constant absolute temperature of 263 K. The observations Contradict earlier work at similar pressures and the disparity is examined in terms of experimental errors.

Movement behaviour of the Little Chief Slide

2011 ◽  
Vol 48 (4) ◽  
pp. 655-670 ◽  
Author(s):  
Mohamed F. Mansour ◽  
C. Derek Martin ◽  
Norbert R. Morgenstern
Keyword(s):  
Steady State ◽  
Creep Behaviour ◽  
Soft Materials ◽  
Steady State Creep ◽  
Reservoir Level ◽  
Dam Reservoir ◽  
Slow Moving ◽  
Pressure Changes ◽  
Reservoir Filling

The Little Chief Slide has been extremely slow moving at a rate of 4–14 mm/year since the late 1960s. The 800 million m3 slide lies about 3 km upstream of Mica Dam in British Columbia. The extremely slow rate was not affected by the Mica Dam reservoir filling in the 1970s. Although the Little Chief Slide is classified as a rock slide, the extremely slow movements take place on seams of soft materials composed mainly of micaceous clay gouge. The characteristics of the movement trends with time were investigated at six zones using in-place inclinometers (IPIs). The trends of the movement with the reservoir level fluctuations and pore pressure changes were investigated to quantify the contribution of steady-state creep to the total in situ movements. The creep behaviour of the clay gouge materials forming the movement zones was also investigated in the laboratory. The laboratory and field creep behaviours were then compared. The movement could be partitioned into steady-state creep and seasonally induced creep movements. This partitioning identified the locations where the seasonal movements are the highest, and, hence, where drainage measures could have the biggest impact.

STEADY-STATE CREEP DEFORMATION OF Cd SINGLE CRYSTALS

2000 ◽  
Vol 11 (4) ◽  
pp. 321-327
Author(s):  
Nazım Uçar, ◽  
Güven Çankaya, ◽  
Ibrahim Karaman, ◽  
A. Ercan Ekinci, ◽  
Bahattin Düzgün,
Keyword(s):  
Steady State ◽  
Single Crystals ◽  
Creep Deformation ◽  
Steady State Creep

Conductivity and NMR Study of LaGa1−xMnxO3 Single Crystals

1999 ◽  
Vol 602 ◽  
Author(s):  
N. Noginova ◽  
G. Loutts ◽  
L. Mattix ◽  
K. Babalola ◽  
E. Arthur
Keyword(s):  
Single Crystals ◽  
Magnetic Relaxation ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Ion Concentrations ◽  
Spin Lattice ◽  
Nmr Study ◽  
Hopping Model ◽  
Mn Doped

AbstractElectrical conductivity and magnetic relaxation has been studied in single crystals of Mn doped LaGaO3 with doping concentrations of 0%, 0.5%, 2%, 10% and 50%. The resistivity of the crystals strongly depends on temperature and can be described with the hopping model. Both activation energy and resistivity coefficient grow significantly with decrease in Mn ion concentrations. Dramatic changes are observed in 71Ga NMR spin-lattice relaxation times.

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