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Below Tβ, α nucleates at the β/β grain boundaries to produce continuous layers of so-called αgb.
Then, colonies of Widmanst¨atten plates called αwgb grow from αgb towards the center of the β grains.
At lower temperatures, acicular α precipitates, refered to as αwi, nucleate on defects in the β grains.
(i) αgb nucleates on the grain boundary (GB) surface.
V and S are the volume and surface. cαβi are the mole fractions at the interface on the α side, and n the number of nuclei with unit volume V ∗ and concentrations c∗i .

Simultaneously, Sn quickly and deeply penetrates along the Al grains boundaries.
Al atoms begin migrate through the liquid layers and fall out on the surface of large grains, while the smaller ones fast dissolve.
The significant hardness increasing in CM points on a strong refinement of their grain structure during the first ECAP.
However, during subsequent passes the grains refining stopped because of an active dynamic recrystallization, and the hardness of the CM does not grow.
During subsequent pressings, some equilibrium is established between the grains refining and its dynamic recrystallization.

Introduction There are large numbers of wide band metal oxide such as TiO2, ZnO, SnO2, ZrO2 and NiO which are potentially used in wide range of applications [1].
Moreover due to the fewer grain boundaries it reduces the electron recombination which providing higher charge transportation.
The grain size of the nanopowders, dXRD was calculated using the Scherer equation.
Using the Braggs law the grain size was calculated.
No high difference in grain size was observed between the rods and the tubes obtained for 4 hours of etching.

The number of unknown variables significantly are reduced by doing this.
Similarly, their storage, transportation and use are all affected by their MC [1]，such as sand and grain.
Consulting a number of literature about this subject, we find that wood MC affects its greatly.
But the disadvantage is the number of unknown variables is big relatively.
In this way, the number of unknown variables will be significantly reduced and the sparse of coefficient matrix is enhanced too.

In fatigue test, the number of cycles to failure is 104~107.
During the conduction of experiments, electronic counter records the number of vibrations, namely: the fatigue life.
With the drawing number increasing, the copper wire is getting finer.
They think both ductility and grain size have effect on copper wires’ fatigue life.
Goto[18] etc. researches the fatigue behavior of a super-fined grain copper rod (with a diameter of 5 m).

XRD results Peak �o 2θθθθ Orientation FWHM d-value Intensity I/I0 Grain size(nm) 1 33.4 (100) 0.236 2.6903 125 100 36 The size of the grains of the MgZnO film was obtained by substituting value of FWHM in the Scherrer's formula [23] as follows θβ λ cos 94.0 =D Where D is grain size, λ(= 1.54059 Å) is the wavelength of X-ray source, β is the broadening of diffraction line measured at half of its maximum intensity in radians (FWHM) and θ is the angle of diffraction peak.
The grain size in MgZnO film was deduced to be 36 nm.
It was noted that the bond position shifted towards higher wave number with corresponding increase in Mg concentration from 0.1 to 0.3 but it is found decreasing at 0.33 mole concentration.
(100) 0 0.4 0.8 1.2 1.6 300 1200 2100 3000 3900 Wave number(cm-1) Absorption(a.u.) 395 400 405 410 415 420 425 0 0.1 0.2 0.3 0.4 Mole concentration Wave number(cm -1) Fig. 2(a) FTIR absorption spectra of Fig. 2(b) Variation of stretching bond positions MgZnO Film with Mg mole concentration The surface morphology of the MgZnO film was studied using Scanning Electron Microscope (SEM) operating at 20 kV and in the scale of 0.1µm for the sample having 0.15 mole concentration.

In order to analyse the grinding process in laboratory scale as well as to facilitate separation of cylindrical bars because of large number of required samples, a simple cylindrical specimen geometry was chosen for the investigations (Fig. 1).
The hard WC grains are cemented by the Co-binder.
According to industry standard an abrasive pencil with bounded diamond grains was used for the investigations.
A huge number of abrasive grains form geometrical undefined cutting edges.
As enhancement of feed and in-feed increase the number of abrasives which are in mesh in a certain time, roughing (IV) achieves the highest removal rates of approximately 7.7 mm³/min.

To ascertain this assumption, the aged material was severely plastic deformed, achieving 94 HVN, and the grain refinement and high dislocations density were the major hardening mechanisms, since the precipitates behavior was similar as the matrix, because particles were distorted instead of acting as impediment to material flow.
It is apparent that the aging temperature plays an important role on the mechanical properties of the Al-8%Ag alloy, because the process at 423 K had a higher Vickers hardness number than the 473 K aging.
After aging and ECAP processing, the hardness values was 94 HVN, and Ohashi et al was 90 HVN result of ECAP processing and aging, both values are close, leading to the assumption that there is no great difference in the sequence of processing, and further strengthening in our system, conducted by ECAP after aging until peak hardness condition, is mainly due to strain hardening, grain refinement and high dislocation density introduced into the alloy, well know phenomena occurring during ECAP processing [8-12].
After processing by severe plastic deformation, was seen that the precipitates tend to flow as equal as the matrix, instead acting as obstacles, concluding that the extra hardening obtained by ECAP process in the alloy, is awarded mainly to cold work, grain refinement and the high dislocation density introduced.

Results showed that even with different grain sizes, and under different density conditions, there were no significant variations in the permeability of the materials.
A number of properties used in engineering can vary with the state of soil compactness, These include shear strength, compressibility and permeability of a soil.
A rise in relative density generally results in greater interaction between grains of sand, which has a direct effect on the shear strength of a material and, in turn, on the angle of friction of the samples.
Irrespective of the tendency to increased strength as a function of relative compactness, if the highest and lowest angle of friction values found for sand S01 and S02 are compared, it can be observed that the values obtained for sand S01 are significantly higher than those of sand S02, which contrasts the notion that grain size determines the strength of a granular material.

The shape of crystals was spherical grains.
This glass has low softening deformation, good crystallization degree, fine grain and good performance during heat treatment, which indicates adopting one-step of heat treatment [10-11].
SEM observations of Fig.4 (S4) and (S5) revealed that three dimensional spherical crystalline growth and a significant number of microspores and micro cracks occurred in the glass-ceramic samples of S4 and S5, as well as S5 contained a large amount of amorphous phase, which can be bring the decrease of mechanical properties.
And the shape of crystals was spherical grains