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The surface atomic number, and specific surface area can increase with the decrease of the particle size, which makes the materials have good optical properties, magnetic, catalytic, etc., in the light absorption, medicine, magnetic medium and catalyst has a wide range of applications [5-6].
Table 1 Average grain sizes and lattice distortion of α-Fe2O3 nanocrystals (a) (b) (c) (d) 2θ(104 crystal face) 33.35 33.23 33.27 33.17 d222(nm) 0.269 0.270 0.269 0.270 average diameter (nm) 34 42 38 36 ε×103 4.68 4.79 4.70 4.70 Fig.3 shows UV-vis spectrum of α-Fe2O3 nanocrystals.

When the size of the prepared particles is less i.e. improvement in the number of grains increases the surface area of the nanoparticles, which can be very much applicable for the field of gas sensors. 100 nm 20 nm (a) 100 nm 20 nm (c) 100 nm 20 nm (d) 100 nm 20 nm (b) Fig. 3.

The input variables are as follows: - design loads of the connection: Fd1 = 43kN; Fd2 = 28kN, - width of the middle timber part: t2=140mm, - material of the middle timber part: Glued laminated timber, class GL24h, - apparent density: ρk=380 kg/m3, - angle between the load directions and the grain of the middle timber part: α = 90°, - characteristic tensile strenght of the bolt: fuk = 800MPa, - iameter of the bolts: d = 16mm, - tensile bolt area: As = 157mm2, - thickness of the outer steel plates: tplate = 8mm, - modification factor: kmod = 0,8, - partial factor for timber: γM = 1,3, - partial factor for bolts: γM2 = 1,25.
We would have to increase the number of the bolts in the girder.

Increasing the hydrogen dilution ratio, the film will be converted to microcrystalline silicon, and a large number of studies show that the stability of the microcrystalline silicon is greatly improved.[4-5] Due to the increase of the operating frequency, VHF-PECVD technology helped to increase the concentration of electrons in the plasma and lower the temperature, which are conducive to the stability of the film's high-speed growth.[6] Thus microcrystalline silicon thin films were prepared by VHF-PECVD under different ratios of hydrogen dilution, and structural characteristics, deposition rate and photosensitivity were analyzed under different hydrogen dilution ratios in this paper.
The most important is the passivation of the grain boundaries in the growth process, which greatly reduced density of defect states.[8] Thus it is can be found that with the improvement of the hydrogen dilution ratio, the film of amorphous components gradually reduced, while the crystal components gradually increased, crystallization rate had been improved.[9] Figure 1.

In recent years, as nanocrystalline powders with ultra-fine grain size promised potentials for changing and improving the mechanical properties of metal and its alloy [8], so a synthesis of the Ti-Ni alloy nanopowders have been received a great attention from the viewpoint of both the scientific research and technological applications.
The value of specific surface area of the Ti-Ni alloy nanopowders was markedly high, which was about 54.8 m 2/g based on a BET method. 20 25 30 0 5 10 15 20 Number of Particles Particle Size (nm) Fig. 3.

If the mechanical energy is used to drive machinery, such as for grinding grain or pumping water, the device is called a windmill or wind pump.
The higher of Turbulence kinetic energy value is good because it can produce large number of blade rotation to generate more electricity.

Therefore significantly reduces the possibility of the grain growth.
As the number of points of computational mesh of this axis is fixed at this step leads to the change and the need to consider the calculation grid deformations in equations (2) - (5).

The main mechanical properties of high-chromium cast iron are; the tensile resistance is about 490Mpa, and Brinell hardness number ranges between 290-340, and it has a good resistance to shocks.
Through the study of the microstructure of the alloy it’s observed the regular distribution of the graines as a result of heat treatments and the presence of homogeneity in the grain size. 4.

Processing is intended to achieve uniform microstructures with fine grains and improved mechanical properties.
Figure 5 a-c shows the microstructure of the base material and the processed material from Exp. 13A with fine and homogeneous grains.
Conclusions · Experimental research for SFSP processing was carried out for EN AW 5754 aluminum alloy of 3 mm thickness under the same conditions regarding the work equipment, the processing tool with conical pin with 4 flat chamfers (Fig. 1b,c), as well as how the liquid working medium is applied to the SFSP processing, the results obtained being influenced by the use of different process parameters and the number of processing passes
· At the microstructural level, fine and homogeneous grains are observed in the processed material, flow lines of the processed material and its mixing zone being visible when processing in multiple passes
Badheka, Recent Development in Friction Stir Processing as a Solid-State Grain Refinement Technique: Microstructural Evolution and Property Enhancement, Crit.

Retention is basically mechanized by irreversible attachment to the rock grain surfaces which itself is impacted by a number of factors including surface roughness, heterogeneity in the charge, and colloid variability [36].
While filtration is a process where the attractive interactions between particles and grain surface irreversibly adsorbs other particles onto the grains surface [37].
In a model for irreversible attachment in a one-dimensional homogeneous media with no salinity and a constant attachment coefficient the results gained indicate that grain size and its dispersivity have the highest impact on transport while porosity impact is less.