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AnHui University of Science and Technology,HuaiNan AnHui,232001 China;3.School of Mechanical Engineering, AnHui University of Science and Technology,HuaiNan AnHui,232001 China aemail:ydchaust@126.com,bemail:mzgao@aust.edu.cn,cemail:chengyunhai2005@126.com, demail:wsheng@aust.edu.cn,email:chenjiasheng2003@163.com Keywords: soft rock composite roof; gob-side entry retaining; deformation instability of filling belt; numerical analysis; measures Abstract:The filling belt of gob-side entry retaining with the character of soft rock composite roof,deforms violently,affected by the fracture and rotation of the main roof,and is prone to instability.This essay,considering characteristecs of coal mine pressure behavior on -790m 1311 (1) working face ventilation roadway at DingJi coal mine in HuaiNan,puts forward structural mech -anics model of the key block of gob-side entry retaining,which is used to forecast the position of the fracture line of the main roof, and analyze the roof subsidence
Fig.1 Surrounding rock key block structure mechanical model of gob-side entry retaining The control over the deformation of the filling belt of gob-side entry retaining is the key to keep surrounding rock stability of gob-side entry retaining.
Three dimensional exploration identifies that there are seven faults in surrounding rock of working face, and five of them affect roadway excavation. roofs and floors rock characteristics on working face is shown in Table 1
The stability of the filling belt of composite-roof gob-side entry retaining in deep mine is related not only to the characters of surrounding rock, the width of gob-side entry retaining and mechanical properties of the filling material and so on, but also to the width of filling belt.
(in chinese) [2] WEN Zhi-jie,JIANG Yu-jing,SONG Zhen-qi etc.Study on mechanical model and surrounding rock catastrophe system of Gob-side retaining entry[J].Journal of Hunan University of Science ＆ Technology (Natural Science Edition),2011,26(3):12-16.

Wiles of Using Hollow Specimens for Fatigue Tests PAPUGA Jan1,a, VARGAS Miguel1,b and RŮŽIČKA Milan1,c 1Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Mechanics.
An unexpected phenomenon encountered during the specimen preparation and testing affected the output of the campaign.
Table 1 Summary of elastic material properties for 6 isotropic materials and the results Material E [GPa] n [-] rasd Material E [GPa] n [-] rasd Al alloy 72.4 0.31 1.71 % Austenitic steel 193 0.28 1.33 % Cu 110 0.31 1.99 % Ti 117 0.31 1.71 % Structural steel 200 0.33 1.99 % W 400 0.27 1.20 % Effect of the Wall Thickness In addition to material parameters, the effect of the wall thickness in the critical cross-section was analyzed.
If the maximum stress should get to the outer surface anyhow, the fillet radius should be so small, that the final notch factor would not allow the experimenters to claim the specimen to be unnotched.
Miyazawa, Fatigue Property of JIS-SNCM 8 Steel Under In-Phase Combined Axial Loading and Torsion, Transactions of National Research Institute for Metals 8 (1979) 35-41

During other periods of time, mechanical ventilation methods are still needed to control the humidity and air quality of indoor environment.
In these situations, in order to avoid affecting the indoor comfort and safety, the top windows of ventilation tower should be automatically closed.
Among of these items of sensors, the indoor CO2 concentration is a key factor for driving HRV to maintain a good air quality.
In the future, other monitoring factors, such as sound, light, water, electromagnetic wave or others can be taken into consideration.
Property Management, 9 Iss: 2 (1991), pp.162-176 [12] ASHRAE, Ventilation for Acceptable Indoor Air Quality, ANSI/ASHRAE Standard 62-2001 (2001), p.25

Introduction Closed cell aluminium foams are lightweight materials of cellular structure with unique combination of physical and mechanical properties, i.e. high specific stiffness, high absorbing ability for mechanical, acoustic, and electromagnetic energies, etc.
Difficult process control causes foam properties to low reproducibility.
Mechanical testing.
As shown in Table 1 average cell size of CaCO3-foams is at least smaller by factor 2 than that of TiH2-foams.
Characteristics Material σy [MPa] σpl [MPa] εD Apl [MJ/m 3] CaCO3-foam 8.5 14.9 0.48 4.4 TiH2-foam 7.0 13.7 0.50 3.9 The cell wall material can largely affect deformation behaviour and mechanical performance of closed-cell foams.

The probable wind conditions under service phase as well as the accurate evaluation on the corresponding results are the crucial factors that should be taken into consideration during membrane structure design.
Structural control, developed in the 1970s, is a new design method to improve the mechanical behavior of the structure by control device in view of classical or modern control theory.
SMA is recognized as the most promising smart material in the structure vibration control for its special shape memory effect, unique super elasticity, high damping, better restorable ability and good fatigue properties.
For example, the project we investigated is located at class B landforms, the highest point is 25m, the reference wind pressure is 0.50KN/m2, the pressure coefficient of height variation is 1.335, the coefficient of wind-induced vibration is 1.9 [3], the shape factor of wind load is 0.4 [4]; according to load code for the design of building structures [5], the static pressure is 507.3 N/m2.
The rigidity of SMA spring is a function of marten site fraction, and the percent content is affected by temperature and external load.

The forward velocity of the cavity is the most important factor which has a pivotal influence for the degree of orientation and residual stress of product [1].
It's RIM module can be used here through changing some process conditions, for example, the maximum injection pressure, material's properties and so on[4].
Fig.8 The expected pressure curve Conclusions In order to keep the forward velocity as smoothly as possible, a detailed study of the most important pressure parameters that affect the quality of the final VC parts, namely, the pressure values, is performed to assure constant forward velocity in the present investigation.
Using this CAE model and BP-NN analysis techniques, together with MATLAB software, the expected pressure curve, the factors that are most significant for serving the filling control system can be achieved.
Acknowledgements This work is supported by Innovation Foundation of SHU (A.10-0109-08-010), Shanghai Science Foundation for the Excellent Youth Scholars (B.37-0109-08-004), and the fund of Shanghai Key Laboratory of Mechanical Automation and Robotics (D.10-0109-09-006).

Influence of microstructure and stress ratio on fatigue crack propagation in TiAl alloy Yanrui Zuo 1,2,a, Zhiyuan Rui 1,2,b, Ruicheng Feng 1,2,c，Dechun Luo 1,2,d, Changfeng Yan 1,2,e. 1Key Laboratory of Digital Manufacturing Technology and Application, The Ministry of Education, Lanzhou University of Technology 2School of Mechanical and Electronical Engineering, Lanzhou University of Technology, Lanzhou, 730050, China azuoyanrui_reena@126.com, bzhiy_rui@163.com, cfrcly@163.com, d119244238@qq.com, echangf_yan@163.com Keywords: fatigue crack propagation; TiAl alloy; microstructure; stress ratio Abstract.
The fatigue crack propagation rate is affected by many factors, such as temperatures, environment, stress ratio, microstructure and Experiments preformed by A.H.Rosenberger [5] has found the influence of environment on fatigue crack growth of γ-TiAl alloys.
Mid-range crack growth rates can be described by the Paris relation as: (1) Whereis the effective stress intensity factor range. is the crack growth rate.
Fatigue properties of TiAl alloys.

Effect of the Friction Coefficient on Large Strain Extrusion Machining Ping Lina, Zi Chun Xieb and Qing Lic School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, China a511086793@qq.com, b375141000@qq.com, cliqing6029@qq.com Keywords: Large strain extrusion machining (LSEM); Bulk nanostructured materials; Deformation behavior; Friction coefficient Abstract.
The material of workpiece is pure copper and the properties for it are as follows: Young’s modulus of 120 GPa, Yield stress of 150 MPa, and Possion’s ratio of 0.3.
Meanwhile the value of the friction coefficient affects the machined surface, as shown in Fig. 4.
In spite of a lot of studies published recently, factors of the inhomogeneous deformation were not elucidated systematically.
Friction is probably the most important factor in all metal forming processes, including LSEM.

Fracturing of the crept specimens was located in the heat affected zone (HAZ) of the F steel.
Some of the most limiting factors are the creep properties of the materials used in steam turbine components.
Microstructural study was performed with the aim of elucidating the causes of creep failure concentrated in the heat affected zone (HAZ) of the F steel.
Hardness was measured to assess the influence of the creep tests on the strength properties in the HAZ of the F steel.
Hald, Microstructure and long-term creep properties of 9-12%Cr steels, International Journal of Pressure Vessels and Piping 85 (2008) 30-35

Study of high-pressure waterjet characteristics based on CFD simulation Liping Cao1,a, Shi Liu2,b,Yaosong Huang1,c and Qian Liu and1,d Zhihong Li1,e 1School of Power, Energy and Mechanical Engineering, North China Electric Power University, Beijing 102206, China 2School of Control and Computer Engineering, North China Electric Power University, 102206 Beijing, China aclp198@126.com, bliushi_ncepu@yahoo.com.cn, chys1986@126.com, dliuqian0607@163.com, elizhihong@ncepu.edu.cn Keywords: High-pressure water jet, flow field, axial velocity, dynamic pressure Abstract.
Nozzle spacing is an important factor influencing the effect of high-pressure water jet cleaning.
The inlet boundary condition: inlet pressure of jet MPa, the volume fraction of water is 1; the exit boundary condition: the exit pressure of jet Pa; wall condition: no-slip wall condition; material property setting: water density is 1000 kg/m3 and viscosity is 8e-04 kg/(m3·s).
If the overlap is too small, within the effective range of a row of nozzles, in some places there will be not good to cover the entire bundle width, thereby affecting the cleaning effect.