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The paper puts forward calculation method and influencing factors of coal wall stability ratio.
According to the pressure date comparison of Tiebei mine two coal faces, setting load is one of important factors inducing roof large area weighting.
The setting load value can affect the working face roof safety directly.
Figure .5 The analysis of shear failure of coal wall (1.7) where C=coal cohesion; =coal friction angle; S=shear stress; h=height of shear failure; q=concentrated load; α=angle between shear plane and coal wall; P=roof pressure; W=sip rock gravity; In Eq.1.7, ;;;,put theses equations into Eq.1.7: (1.8) According to Eq.1.8, coal wall stability coefficient is concerned with coal mechanical properties and concentrated load.
(4) The obeservation showes that low setting load is one of the important factors which cause working face roof cuting in large area.

The results will provide necessary reference for the further optimization design of condenser. 1 Introduction The application and development of the once-through boilers and nuclear power devices in the electricity industry lead to higher requirements for condenser performance [1].To analyze the stiffness and strength of large-scale condenser by using economic and efficient methods, it is particularly important to instruct condenser optimization design and to study the mechanical operation properties of the condenser components.
Similarly, air cooling zone of the tube sheets and air-cooled equivalent entity is also set bonded. 2.3 Mechanical properties of the tube sheets materials and condensing tubes As the tube sheet is a composite of different materials, we need to calculate its equivalent results.
These equivalent results of material mechanical properties in this paper are calculated according to relevant standards HEI.
Table2 Equivalent Mechanical performance parameters of tube sheets and tubes machinery performance equivalent elastic modulus[MPa] allowable stress Sm[MPa] perforated area 41147.12 50.23 unperforated area 189481.43 173 equivalent condensing tubes 5080 132.7 3 Results and analysis Stress and deformation are two main factors in finite element analysis.After calculation, the results of stress and deformation of condenser components are shown in Figure a~g, and the maximum equivalent stress and maximum deformation of components are shown in Tab. 3.
Mechanical Design( Higher Education Press, 2006)

Only increasing structural size and improving material property are not efficient to prolong service life.
The valve box is made of 34CrNi3Mo, whose mechanical property are as follows: tensile strength σb=1050MPa, yield strength σs=850MPa and tangent modulus t=2*1010Pa.
When the time of loading, stabilizing and unloading are longer than 60s, different loading time affects hydraulic self-enhancement results hardly. 4)The optimal self-enhancement pressure is decided by the maximum working stress and Bauschinger Effect Factor.
MECHANICAL RESEARCH&APPLICATIO, 2008, 21(6):21~23
JOURNAL OF MECHANICAL STRENGTH, 2000,22(2):146-148.

Introduction In daily life, due to a lot of reasons and factors lead to the mechanical equipment or parts failure.
With the development of the modern science and technology, the requirements of mechanical safety and reliable operation is more higher.Failure analysis on fracture can grasp the cause of the accident, so it is particularly important.
Due to the influence of the external environment, conversion device accuracy, noise interference and transmission information loss and so on, Failure image quality will be affected during the image acquisition process, then affect the late recognition and analysis.
Mathematical morphology pretreatment Due to the influence of external environment factors, fracture images in collected will under the influence.
It focuses on the collection of image structures, This structure can not only describe the macroscopic properties about the research object,but can also said its microscopic properties.

In fluid drive system, instability will happen in the influence of load when fluid drive clinder runs in low velocity, which will affect the system’s stability and reliability.
Simulation model of hydraulic clinder performance Fig8. curve of hydraulic clinder As shown in Fig.8, we can easily figure out the factors such as friction, Viscous damping coefficient, compressibility coefficient, leakage coefficient ,which can effect features of curve of hydraulic clinders.
In order to verify the mechanism of vibration caused by the coupling force, and investigate the law of influence on low speed characteristics of hydraulic cylinder affected by different essential factors, a variety of dynamic testing for hydraulic cylinders have been conducted including displacement, velocity, acceleration tests based on Hydraulic Test Stand shown as fig.9.
Results and Discussion From the perspective of nonlinear dynamicsandnonlinear dynamic test, the reasons why hydraulic clinder creeps in low velocity are verified that is the combined result caused by many factors in specific working state such as jump phenomenon, self - excited vibration, etc.
China's mechanical engineering ,19(24):2930-2933.Vol.19(2008),p.2930

Currently for the restoration of worn functional surfaces or the production of surfaces with properties exceeding the properties of base material often the processes of arc welding are used.
In the paper there is a choice of particular components presented, surfaces of which are worn by the combination of various tribodegradation factors in the operation.
As the abrasive medium aluminum oxide was used (Fig.6), the physical properties of which are shown in Tab. 7.
Conclusions The paper presented options of the components renovation, surfaces of which are exposed in the operation to extreme tribodegradation factors.
From these factors the most common are abrasive-adhesive wear combined with impacts, high surface pressures as well as corrosion.

This paper puts forward a kind of mechanical measurement method—Heavy hammer-level meter detection based on investigation and research around the Hubei power plant.
The difficulties of ash level measurement Coal ash in the storage has some properties such as light weight, dry, small particle size and low dielectric constant, etc. [5].
These properties result in level measurement of material difficulties are as follows: The dielectric constant of the ash is low, it leads to ultrasound and radar can not form strong reflection.
Coal ash is easily affected by temperature, rain and other external environmental impact [6], medium surface reflection intensity varies because of the environment, it　will affect the accuracy of the instrument.
Heavy hammer-level meter is widely used because it is not affected by the dielectric constant, dust concentration, reflective surface and other factors [7].

In machining operations, the behavior of the material is influenced by factors such as the type of tool used (material and geometry) that evolve over time due to technological advances.
Diameters for delamination factor (DF) calculation Statistical Methods.
Thus, the behavior of these two composites is very similar in the delamination factor analysis.
- PEEK-GF30 and PA66-GF30 have a similar behavior regarding delamination factor, being the type of fiber a critical factor.
Alarifi, A Review on Factors Affecting Machinability and Properties of Fiber-Reinforced Polymer Composites, J.

Table 1 summarizes the properties of herb residues.
Table 1 Properties of herb residue Fuel Herb residues Proximate [wt.%] Moisture 12.5 V 72.62 FC 12.41 Ash 2.47 Ultimate [wt.
Results and discussion Temperature and pressure profiles Operating temperature is one of the most important factor affecting the working performance of the fluidized gasifier, and T1, T3, T5, T7 are chosen to represent the temperature of the riser.
The results indicate that the biomass and air feed rates are important influencing factors of the temperature.
Effect of O/B The O/B ratio (g/g) is a crucial factor that affects the performance of the gasification process.

Probability theory determines how the uncertainties in crack size, loads, and material properties, when modelled accurately, affect the integrity of cracked structures.
The method can account for random loads, material properties, and crack geometry.
,X characterizing uncertainties in the load, crack geometry, and material properties.
The calculation of stress intensity factor affected by the randomness of crack size, elastic modulus and far field applied stress magnitude.
The load, crack size and material properties were treated as statistically independent random variables.