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Domestic or industrial activities, as well as natural phenomena, are among the risk factors that may cause ignition [2, 3].
This behavior can be tailored to the needs of certain applications by altering the water content in the magnesite mixture or the annealing temperature to obtain MgO powder, both affecting the microstructure and the properties of the obtained heat-insulating material, similarly to magnesium potassium phosphate ceramics [20, 21].
Kovalov, et al., Parameters of fire-retardant coatings of steel constructions under the influence of climatic factors.
Nevřivová, Study on the properties of geocement based thermal insulating materials for high temperature technical appliances, AMR. 734-737 (2013) 2356-2359
Kopylova, Study on physico-mechanical properties of the modified alkaline aluminosilicate adhesive-bonded timber elements.

Choice of the way of tunnel excavation is crucial factor affecting deformation of surrounding rock, especially deal with complex geology as soft rock; extremely soft rock condition which strength is low, the capacity of self-stabilization is rather weak.
In fact division method mentioned in this article is three heading excavation method, which is compared with central heading full section and central heading step method by construction practice and finite element soft ware to explore the factor of affecting deformation of surrounding rock, the time effect of rock deformation [4, 5], put forward relative conclusion and offer references for similar projects.
Tunnel groundwater mainly gather in the weathered strong weathering layer, permeability coefficient K=0.1~0.6m/d, physical mechanical proprieties index of surrounding rock determined indoor test is shown in Table 1 Table.1 Physical and mechanical properties of surrounding rock material Bulk density λ(kg/m3) Poisson's ratio μ Modulus of elasticity E(Pa) Angle of internal friction Φ Cohesion C(Pa) 2400 0.3 96440000 25o 8000000 Monitor and analysis of surrounding rock deformation of tunnel The key point of deformation control of surrounding rock contains loosing stability of working face, loosing stability of vault, sink of arch foot and deformation of surrounding rock during tunnel excavation [6].
Analysis on construction factors of surrounding rock deformation in tunneling works [J].

Study Friction Between Wheel and Rail by Using Molecular Dynamics Method Qian Xiao1, a,Ming Mu1, b,Xinjian Zhou1,c,Yuxiang Che1, d 1the Ministry of Education Key Laboratory,carrying tools and equipment,East China Jiaotong University, Nanchang,Jiangxi,330013,P.R.China jxralph@qq.com,muming803@163.com,zhouxj@ecjtu.jx.cn,407318848@qq.com Keywords: Embedded atom method , Molecular dynamics, friction , wheel-rail rolling contact Abstract.Aiming at researching friction process on the influence of train rolling contact properties between the wheel and rail,using the basic principle of Molecular Dynamics Simulation and Embedded Atomic Method theory,study the areas of adhesion within the contact patch area will gradually increase along with the occurrence of the friction process,research the increase process about the areas of adhesion within the contact patch area by means of Molecular Dynamics simulation model and simulation algorithm.For the study of friction on the surface about changes
Introduction Due to the limitations of experimental methods, experimental methods can not only through a thorough understanding of the microstructure of metallic materials, material transformation, mechanical properties and its internal mechanisms.
Fig. 1 Wheel-rail contact model The Process of Molecular Dynamics Simulations Model Duilding.Between wheel and rail, there are the following factors: contact with the surface roughness, normal force size, the nature of surface contamination, the water film, film layer, temperature, relative sliding speed and so on[1].
By these factors affect the friction between wheel and rail rolling contact role, the study process to iron oxide as a molecular dynamic simulation of power ideal material, the molecular layer was40 ×40 ps.Fig.2 shows 3d molecular dynamics model.

Several measurement techniques were used to assess the properties of the developed mats.
PAN was selected as the spinnable polymer since it is easily electrospun and offers plenty of superior properties, such as higher hydrophobicity, excellent mechanical, thermal stability, and insolubility in a wide range of solvents.
Another factor that is related to the fibre’s morphology and affects fibre’s conductivity is the aspect ratio.
PAN was selected as the spinnable polymer since it is easily electrospun and offers plenty of superior properties.
Pittman Jr, “Preparation, electrical and mechanical properties of vapor grown carbon fiber (VGCF)/vinyl ester composites,” Composites Part A: applied science and manufacturing, vol. 35, no. 6, pp. 693–701, 2004

Al alloy/SiC composites possess better mechanical and physical properties thus finding applications in automotive, sports, and aerospace.
These properties determine the aggressiveness of the abrasion.
Workpiece properties, process input conditions, component geometry, and medium properties are the most important factors that affect the performance of the process.
Soft styrene butadiene provides the dominating elastic and partial viscous properties.
At low plasticizer to polymer ratio, polymer dictates the medium properties (i.e., elastic properties are dominant).

The factor limiting the further use of these alloys is their poor room temperature ductility.
Alloying Ni-Si alloys with transition metal elements such as Cr, Nb and Ti have resulted in significant improvement of the properties of the composites [1-7].
Alloying with Cr was demonstrated to have positive influence on mechanical properties of Ni3Si-based alloys especially on ductility and corrosive properties [3].
The improvement of corrosive properties in sulfuric acid solution was also investigated.
The microstructures of coatings are affected greatly by the addition amount of Cr.

Also, a coarsening rate of primary solid phase was not considered to be affected significantly by a holding temperature even though a little lower coarsening rate was obtained at the higher holding temperature.
Introduction As known to many studies for semi-solid processing (SSP) in comparison with conventional casting, it has been recognized that SSP can offer many advantages such as less energy consumption, long mold life due to casting at semi-solid region and it is possible to produce the product having the superior mechanical properties as well as the near net shape of complicated product without defects [1-2].
Also the holding temperature was related to a volume fraction of solid phase of semi-solid slurry and can affect a flow behavior of semi-solid slurry during the rheocasting process.
The size of primary solid phase was largely affected by a holding temperature.
Because the slurry has the fine and globular structure required in rheoforming process under this condition or else too coarsening particle has affected on the mechanical property of product.

It is essential that the mechanical and thermal properties of the joints should meet the requirements of engineering.
In view of the fact that the ternary carbide Ti3SiC2 has shown unique mechanical and thermal properties, it is promising to join SiC to SiC using ternary carbide Ti3SiC2 as filler (welding compound), and this is the subject to deal with in this paper.
As a key factor for the application of the ceramic, joining of SiC to SiC has been investigated for some years [3,4].
It is anticipated that the favourable high temperature properties of Ti3SiC2 will contribute to the high temperature properties of the joints, and its plasticity will benefit the thermal stress relaxation.
The weld strength is strongly affected by the technological parameters.

Results which are obtained using the two – phase mixture model indicate that adding the nanoparticles causes changes in the properties of nanofluid and finally increases the temperature of the flow.
However, due to the fact that the effective properties of nanofluids are not known precisely, the numerical predictions of this approach are, in general, not in good agreement with experimental results.
Therefore, the concerns in single phase modeling consist in selecting the proper effective properties for nanofluids and taking into account the chaotic movement of ultra fine particles.
Due to several factors such as gravity, friction between the fluid and solid particles and Brownian forces, the phenomena of Brownian diffusion, sedimentation, and dispersion may coexist in the main flow of a nanofluid.
The physical properties of the fluid are assumed constant except for the density in the body force, which varies linearly with the temperature (Boussinesq’s hypothesis).

All above factors can promote the initiation of the fatigue cracks considerably.
Materials Properties (1) The properties of 247# super alloy The material of the sealing disk is 247# super alloy, the material properties are as follows:Density ρ=8320kg/m3; Poisson’s ratio μ=0.3.
Table 1 The Mechanical Properties of 247# Superalloy at Different Temperatures T [℃] 20 650 750 E [GPa] 201 179.5 171.9 б0.2 [MPa] 755 686 686 бb [MPa] 1205 1127 931 Table 2 The Linear Expansion Coefficient of 247# Superalloy at Different Temperatures T [℃] 20~100 20~200 20~300 20~400 20~500 20~600 α[10-6℃-1] 12.5 12.9 13.3 13.7 14.0 14.4 (2) The Mechanical Properties of 79# Powder Metallurgical Material The material of the sealing disk is 7No.9 powder metallurgical material, its properties are:Density ρ=8360kg/m3; Table 3 The Elastic Modulus and Poisson’s Ratio of 79# Powder Metallurgical Material at Different Temperatures T [℃] 20 300 500 650 700 E [GPa] 214.7 208.6 197.6 189.6 186.4 μ 0.307 0.317 0.328 0.337 0.340 Table 4 The Linear Expansion Coefficient of 79# Powder Metallurgical Material at Different Temperatures T [℃] 20~100 20~200 20~300 20~400 20~500 20~600 α [10-6℃-1] 11.1 11.6 12.1 12.7 13.0 13.2 It is specified in the material specification of 7No.9 material that, while
(2) Design structure According to the cyclic symmetry properties of the sealing disk model, a 45°fan-shaped segment is made to be the calculation model, see Fig.13.
Tian: The Basis of Failure Analysis (Mechanical Industry Press, 1989) [8] Donghan.