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Grain-boundary diffusion in the Hwang-Balluffi model.
In this regime, volume diffusion is essentially frozen out so that the material transport takes place only within the grain boundaries without any leakage into the adjoining grains.
They assumed that the atoms arriving from the grain boundaries spread out on the surface.
This Hwang-Balluffi relation is given by: ( ) ( )'exp1// 0 t cckk s ω−−=''' , (1) khD sb ' = δλδω / . (2) Here λ is the grain-boundary density (e.g. for a polycrystal having cubic grains with a lateral size d, λ = 2/d). k' is the segregation coefficient at the accumulation surface/grain-boundary interface and k'' the segregation coefficient at the grain-boundary/source interface.
Although, JI also decreases with increasing time/number of layer dissolved, but Jβ decreases much faster.

Columnar grains were generated in the steel near the interface by the heat treatment at 1223 K and above.
Ferrite grains in Table 1 Chemical compositions of materials.
The formation of columnar grains is closely related to constituent phases at the bonding interface.
A large number of relatively small grains are clearly seen in the vicinity of the interface, while the adjacent columnar grains have different orientations each other.
The orientation map for the growth direction of the columnar grains also showed the same tendency.

The reorientation of two grains in the gauge area was measured using EBSD.
The total number of cycles was 20 and the specimen was not fractured.
The orientation of the grains in the gauge section was evaluated using EBSD detector from OXFORD Nordlys Max.
The activation of secondary slip system is probably due to small rotation of the grain which was measured by EBSD.
Only a small but important irreversibility develops in the form of extrusions and intrusions in the surface at locations where PSBs emerge on the surface and where fatigue cracks initiate at larger number of loading cycles.

Metallographic tests of the material show a fine-grained ferritic-pearlitic structure (Fig. 2, ferrite (light grains) and pearlite (dark grains)).
An average diameter of the grain in the crack growth direction was about 20 mm.
Further evaluation results in indentifying additional intercrystalline cracks along the boundaries of grains.
The fatigue tests were performed for a high number of cycles under the stress ratio R = - 1.
Fig. 5 presents the fatigue crack growth versus a number of cycles for proportional bending with torsion under different ratios MaB / MaT.

The wire substrate is 65Mn steel and the size of diamond grains is 50/60, 60/70, 70/80, 80/100 US mesh.
This is because the increasing normal force, on the one hand, increases the pressure of single diamond grit depth, on the other hand, the number of grains of diamond for cutting has also increased, so that the material removal volume increase, with an area larger[6].
This is because as the wire saw speed increases, the cutting depth of single grain decreases, but the unit time to participate in cutting the number of diamond particles increases, the overall removal volume increases.
An increase in the feed tension results in the increase of cutting efficiency due to increase of the pressure of single diamond grit cutting depth and the number of grains of diamond for cutting.
The cutting efficiency is increased with the increasing wire saw line speed due to the increase of the number of diamond grains participating in cutting per unit time.

But the majority of the fragments marked with number in Fig.2 resulting from such cracking could be cold rolling, without further cracking [8].
(a) 2h (b) 3h (c) 4h However, as is known to us, with the increase of the holding time, grains are growing, which decrease grain boundaries that can hinder domain rotation, thereby enhancing magnetic properties while lowering yield strength.
Recovery, recrystallization and grain growth will take place during isothermal heat treatment after a large reduction of cold rolling.
And their average grain sizes we calculate based on the stereological method are 23um, 27um, 34um respectively, that is to say, with the extension of holding time, the grain is growing gradually.
However, due to grain refinement, the grain boundary would increase, which make the domain rotation more difficult, thus may reduce the magnetic properties.

Introduction Soil is particulate structure, the skeleton unit like simple grain and collective grain contributes to spacious structure.
The relation between strain and stress is controlled by shape, size and contact relation of soil grain, which are structure characteristics of soil.
Therefore, there is a relationship between void ratio e and particle number n, long axis L, short axis B, x, y coordinate of the centroid, y-axis projection length of sand particle.
Therefore, there is a relationship between shear stress and particle number n, long axis L, short axis B, x, y coordinate of the centroid, y-axis projection length of sand particle.
First, there is a quantitative relationship between water content w and particle number n, the length of long axis L and short axis B of the sand particle.

In order to decrease test number，strengthen veracity of test result，orthogonal test is a good method（see table 1）.
As shown in the Fig.3, with the diminution of the size of abrasive grain, the roughness of the workpiece surface is decreasing.
The reason is that the score and the apophysis of the surface reduce as the diminution of the size of abrasive grain in the process.
As with the increase of linear velocity, in unit time the number of abrasive grains in the grinding area is increasing, the depth of cut for single grain and deformation of workpiece surface are decreasing.
Meanwhile it shorten the contact time between workpiece and abrasive grain, decreases the height caused by grains' plough and thermoplastic deformation, the surface roughness is also decrease.

The blade material, verified as IN738LC nickel superalloy, exhibited presence of elongated grain boundary carbides, TCP phases formation, and grain boundary creep void on the airfoil.
Large numbers of start-stop of peaking duty gas turbine, which is applicable in present study, is known to accelerate thermal-fatigue cracking.
Besides microstructures of IN738LC and weldment, surface replication also reveals presence of distinguishable fine equiaxed grain microstructures as shown in Fig. 4.
It was observed that airfoil base material appeared to be degraded as evidence by presence of continuous grain boundary carbide, deleterious plate-like TCP phases (Fig. 5 (a)) and grain boundary decohesion which is normally associated with creep damage (Fig. 5 (b)).
There are also evidences of microcrack propagated through grain boundary perpendicular to the weld junction (Fig. 8 (c)).

A series of burning tests are conducted with different grain orientations, viz., vertical, inverted and horizontal.
The modelling of solid propellant combustion serves a number of useful purposes in the scheme of propellant development.
Photograph shows that the upper regions of the inner surface of the star grain is burning faster than the lower surface.
The end burning grain was cast using Polyvinyl Chloride (PVC) pipe at the desired length and diameter.
This inference is corroborated with our in-house experimental investigations on end burning grains at atmospheric conditions with different grain orientations, viz., vertical, inverted and horizontal.