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As known from linear, irreversible thermodynamics [8], the driving forces for the motion of charged species (index i) are the gradients of their electrochemical potentials, , where mi is the chemical potential, zi the charge number, F Faraday’s constant, and F the electric potential.
If the formation of the oxide layers is determined by bulk and/or grain-boundary diffusion processes, one obtains parabolic rate laws for the thickness of each oxide, Dxi(t) = (2kit)1/2 (i = CoO, Co3O4).
As discussed there, the relatively high value is probably due to a significant contribution of fast cation diffusion along grain boundaries within Co3O4.

The electrical conductivity depends on the heating temperature (T), the heating rate (T) and the grain size of the material.
The relative permeability depends on the frequency (f), the magnetic field strength (H), the heating temperature (T) and the grain size in the material.
Furthermore, using an experimental design based on strategies such as orthogonal arrays (MO) developed by Taguchi, usually leads to designs like fractional effective and robust to obtain statistically significant information with a minimum number of simulations.

It is well known that aluminum alloys can be strengthened by a number of mechanisms such as particle dispersion hardening, solute hardening, age hardening precipitates and grain size reduction.
Among these strengthening mechanisms the age hardening precipitates and grain size reduction in the production of fin stocks for automotive applications are difficult to obtain due to the high temperature brazing treatment.

There are no grain boundary and dislocation in their structure therefore they exhibit superior properties when compared with similar crystalline counterparts.
Results show that under the same drilling conditions the micrograin carbide tool, submicron size carbide grains in it, generally requires less thrust force than solid one.
Acklowledgement A portion of this research was sponsored by The Scientific and Technological Research Council of Turkey (TUBITAK) under the project number 107M443.

Cr2O3 particles can be as dislocation sources, are able to increase the density of dislocations, and block the movement of dislocations on grain boundaries and sub-boundaries, thereby improving the strength of the Cr2O3/Cu composites [9].
Owing to the presence of uniformly dispersed and high electrical erosion-resistant Cr2O3 particles, a great number of particulates composed of copper-coated Cr2O3 particles form on the surface and in the matrix of Cr2O3/Cu composites.
Fig.5 EDS of the worn surface of 1.1Cr2O3/Cu composite（45N,5m/s,30A) In the Cr2O3/Cu composites prepared by internal oxidation of Cu-Cr alloy, the dispersed Cr2O3 nanoparticles serve as sources of dislocation to increase its density, which exert pinning effects on the dislocation and grain boundaries during deformation and annealing treatment.

., TM-D, average grain size 0.19mm, a-alumina) and Y3Al5O12(YAG) (Shinetsu Chemical.
Ltd., RYAG-OCX-076, average grain size 1.1mm) powder (weight ratio; 95:5) were used as raw materials for the green sheet.
Number of bending strength measurement was 15~17, and the Weibull modulus of the maximum strength was obtained.

The constitutive relations of an isotropic linear poroelastic medium can be expressed as ij kkij ij Gεελδσ 2 ' += (4) in whichλ is Lame's constant, G is the shear modulus in Pa, ν is the Poisson's ratio, δij is the Kronecker delta defined as 1 for i=j and 0 for i≠j, and the effective stress tensor in Eq.(4) is also given by the relation pijijij αδσσ −=' (5) where σij is the total stress tensor in Pa, α is the Biot's effective stress coefficient which depends on the compressibility of the constituents, which is a positive constant equal to 1 when individual grains are much more incompressible than the grain skeleton, and p is the pore fluid pressure in Pa, negative for suction.
These numerical results are supported by a number of experimental observations reported in the literature [18]. 0 0.05 0.1 0.15 0.2 0.25 0 0.0002 0.0004 0.0006 0.0008 0.001 0.0012 0.0014 0.0016 Strain Permeability/(m 2/(MPa2d)) m=1.5 m=3 m=5 Fig. 2 Simulated permeability-strain curves Fig. 4 (a) Simulated rock failure process, (b) gas pressure gradients, (c) AE counts, and (d) the volume of flow for rock specimen (m=1.5) As we know, one method of observing damage or microcracking during rock deformation experiments is by monitoring the acoustic emissions (AE) or seismic events produced during deformation.

To remedy this, a number of wires is placed next to each other.
As long as the stress on the different lattice planes doesn’t vary to much as a result of grain-grain interactions, the calculated value for the stress is considered to be a reasonable approximation for the stress in the cementite phase.

As have been reported in the literature for similar FSW processes [9,14], the microstructure of the central portion of the joints, SZ, has been dynamically recrystallized and present a fine-grained, equiaxed microstructure, Fig. 3(c).
Adjacent to the SZ, a thermo-mechanically affected zone (TMAZ) was formed on both welding sides (AS and RS) and highly deformed grains resulting from the material flow were observed, Fig. 3(d).
As the RSp increase, the number of revolution per millimeter carried out by the tool increase (higher weld pitch), and these marks systematically tend to come near to each other.

On the other hand, cast train wheel requires cheaper costs both initial investment and production costs for a limited number of products [1, 2].
Microstructure Observation The specimens after the casting, normalizing, hardening, and tempering processes were polished by using emery papers (#320 up to #2000) followed by an alumina suspension with a grain size of 0.3 μm, and then they were etched using a 3% nital solution.
In addition, cast products usually produce coarse grain sizes.