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Introduction Sapphire crystal, for its excellent mechanical and optical properties, has been gradually applied in many popular areas such as defense and civilian, which requires high processing efficiency and surface quality of sapphire [1-3].
However, because sapphire has high hardness, brittleness and chemical stability properties, it is difficult to efficiently get high-quality of surface finish [4-5].
The two factors mentioned above cause the difference between experimental results and theoretical estimation Fig.7 shows the schematic illustration of ideal surface profile.
[14] Y W Zhu, J Wang, J Li, K Lin, China Mechanical Engineering, 20(2009):723-727
[15] Z C Lin, W S Huang, J S Tsai, Journal of Mechanical Science and Technology, 26(2012): 2353-2364.

They provide the opportunity for a well-directed change of the local structure associated with the surface layer properties, especially when additional alloying elements (e.g.
The mechanical properties (Fig. 2) were examined in relation to the untreated base material (BM) as well as the EB remelting layers (EBR).
With regard to the representative layer properties, the increase achieved by EB remelting is relatively small.
EB remelting decreases k by a factor of 4.5.
Influence of EB surface treatment on layer properties (AlSi35) An EB multi-process technology was developed for surface alloying of Al alloys to improve the layer quality (porosity, crack sensitivity, surface deformation) in connection with lower production efforts (e.g. mechanical finishing).

However, welding parameter are very important factor that affect to quality, and reliability of parts because an improper welding can cause decreased tool life [1-3].
The material of low weldability, such as SKD 61 hot work tool steel, undesirable hardness influenced by thermal distribution in any repair welding and especially near the bead area or heat affect zone (HAZ) is very essential factor which has an effect on material properties.
This unique structure has a strong influence on hardness properties.
The effect of welding on hardness properties.
Mar drl Plata (2005) [10] Leshchinskiy L.K, Samotugin S.S: Mechanical properties of plasma-hardened 5% chromium tool steel deposited by arc welding.

While these factors not only depend on machining parameters but in the same degree on the material to be cut and vibrations occurring in the process a complete evaluation of the single factors and their interrelations was done.
Key Engineering Materials Vols. 241 Stone Material Properties.
Material properties are the main influencing factor on machinability beside machining parameters [2].
It is common to use either the mechanical properties, strength and hardness, or the mineral composition as value to characterise the machining patterns of the rock material [8].
For this reason investigations were carried out to characterise grain size and mineral composition of the materials and to evaluate the mechanical properties and machinability of the rock.

It affects a lot of soil ecosystem services.
Pyrolysis processing factors such as temperature, residence time and oxygen absence affect surface characteristics of biochar a lot [6, 10].
Previous research reports that the potential impact of biochar amendment improving soil water holding capacity depend on feedstock, pyrolysis conditions and soil properties [11].
Results and Discussion Soil and biochar properties The biochars used were produced from softwood and walnut shell, which are two kinds of main feedstocks of biochar.
According to the different demand of agriculture practice and the variability of soil and biochar, we chose soils and biochars with representative properties in this study.

Table 1 Material property for the numerical model The contact force, frictional force, load on the tunnel liner can be calculated and the safety factor of tunnel liner can be analyzed with the numerical model of tunnel by contact method.
Except for mechanical property of surrounding rock, cover depth, tunnel width, release factor and shape of void may also influence the distribution of rock pressure on tunnel liner.
Depth, Width of Void and Safety Factor.
Fig.8 Influence of void depth in arch Fig.9 Relationship of width of void and safety factor Circular Width and Safety Factor.
Void in arch influences crown most and arch and side is also affected, so void in crown may induce crack or exfoliation in crown and side wall.

The question of fundamental interest for materials science is whether these materials can be ascribed to a new class of solids having distinct properties in a way similar to nano-materials or metallic glasses, or, alternatively, their properties can be logically predicted by expanding the presently available knowledge about ordinary polycrytslalline metals.
Using transmission electron microscopy, including high resolution, they have demonstrated that namely heavily distorted grain boundaries with excess grain boundary dislocations and other defects formed during SPD appeared as a unique feature of SPD metals, affecting most physical and mechanical properties.
Hence, these materials may inherit some properties from both crystals and glasses, while potentially remaining distinct from both of these extremes.
(1) where /2uF is the stress amplitude, Kb and n' are material properties.
This phenomenon is affected by a many structure sensitive factors and testing conditions.

Welded joints are fracture initiation points because of the effects of microstructural and mechanical inhomogeneities [1], and residual stress induced by welding is one of the most important factors in reliability diagnosis.
However, they suffer from the difficulty of separating microstructural effects on physical parameters from the effects of residual stress, since all these techniques are highly sensitive to metallurgical factors such as grain size and texture [3].
Hence a new mechanical testing method for residual stress evaluation is needed.
The instrumented indentation technique, which measures load and depth continuously during indentation and analyzes load-depth curve, has been developed for evaluating hardness, elastic modulus, tensile properties and the like [5, 6].
In addition, the stress directionality factor k was pre-determined and non-equi-biaxial stress states could be considered.

These provide indications reflecting both mechanical and micro-architectural properties of bone tissue.
(7) is the structure factor.
The main structural and acoustic properties of cancellous bone used to simulate the propagation of the ultrasonic waves in cancellous bone are listed in Table 1 [6].
This parameter does not affect the speed of the fast wave.
It affects the different ultrasound propagation speeds in the porous material.

Interface nonlinear affect dynamic stiffness considerably.
However, due to some uncertainties non-linear factors, it is difficult to predict contact behavior and analyze non-linear characteristics.
The material properties are assigned respectively, including elastic modulus E=2.1×105MPa, Poisson ratio , and density In this analysis, the contact relationship to be built occurs respectively between two sheet metals and between the sheet metals and a combined bolt-nut.
It indicates that the proper pretension effect will make the dynamic behavior of connected plates better under non-linear factors.
Journal of Mechanical Engineering Science. 223(2009) 363-375