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The mist particles grain dust fall through the combined effects of inertial impaction mechanism, interception mechanism, Brownian diffusion mechanism, charged catching dust mechanism and sound coagulation mechanism[6]. 2.1 The dust removal effect of uncharged mist particles: dust removal efficiency is shown in Figure 1 From figure 1 we can see, water mist particle uncharged has low capture efficiency in dust catching with diameter under 10 μm (especially for 0.1 ~ 2 μm ), and the particle has high capture efficiency to the dust with diameter above 10 μ m.
Research shows that, the respirable dust capture efficiency increases monotonically with water spray particle speed and spray water flow increasing, as well as fog grain diameter decreasing.
This is the reason why high pressure spray has notable dust-settling effect on respirable dust. 75 100 125 5 10 15 20 25 30 Spray water pressure p (Mpa) 1 2 0 25 50 Volume charge density/ (charge number/cm3) Figure 5 The relationship between charge and spray water pressure of water mist 1- negative charge; 2- positive charge In summary, because of the small diameter and high velocity of the mist particles, high pressure spray has high dust-settling efficiency for un-respirable dust.
high-pressure sprayers high-pressure rubber hose pool filtering the water tank high-pressure pump the throttle valve equipment pit crusher feeder machine Figure 6 High pressure spray system arrangement Major equipment technical parameters · category parameters number note high pressure spray Nominal flow rate 75L/min Pressure of work≤12MPa 1 Form a complete set of motor:18.5kW,voltage:380/660V; spray pressure of work:8～10Mpa; the spray flow rate:32L/min.
Automatic water tank Volume 500L 1 set of With filter function Step-down startup control cabinet 1 Precise instrument of filter water 4 High-pressure rubber hose Ф25/Ф13 60m High-pressure sprayers 8 Pressure relief valve 1 High pressure rubber hose fittings 1 set of Quick clamp, tee, straight and high pressure valves, etc Major equipment Parameter Number Remarks High pressure pump Flow rate 75 L/min Working pressure≤12MPa 1 Power generator 18.5kW, voltage 380/660V; working pressure: 8～10MPa; spray flow rate: 32L/min Self-control water tank Volume 500L 1 Filtering capability Step-down control cabinet 1 Precision water filter 4 High pressure hose Ф25/Ф13 60m High pressure sprayer 8 Pressure relief valve 1 High pressure hose fitting 1 Quick connect card, three-way valve, through valve, high pressure valve, etc. others Conclusion This research complete the design and installation of a high pressure ejector spray dust-settling system in an crushing station , making

Introduction Serration behavior has been observed in a large number of alloy systems.
When a strong pile-up stress is built up, the precipitates will be sheared and a large number of dislocations could move collectively through this passage (or series of passages) giving rise to a stress drop [10].
It would be reasonable to think that the density of mobile dislocations is lower in peak-aged and 1 min reversion treated specimens, because the smaller spacing of d¢-particles in the two specimens may result in a higher dislocation density and a slower average dislocation velocities like the description, i.e. the dislocation density is higher and hence the average dislocation velocity slower in fine grained specimens than in coarse grained specimens at the same strain [12].
On the other hand, the number of dislocation pile-ups in front of d¢-particles in the two specimens is fewer because of a short d¢- particles spacing, and thus no enough strong pile-up stress is built up in the front of the particles to shear them.

In order to remove the scratches on the surfaces, the mounting was then polished using alumina solution starting from grain size 6.0 µ, followed by 1.0 µ, 0.3 µ and 0.01 µ.
Nitol was then applied to the surface to reveal the grain boundaries of the ferrite and pearlite.
Secondary serrated teeth also happen to appear at the free or constrained edge of the chip resulting from the coagulation of a certain number of primary serrated teeth as shown in Fig. 5.
It is also observed that the number of secondary serrated teeth is less with ultrasonic machining.
In case of machining with ultrasound, the tooth of secondary serrated chips is larger and the number of secondary serrated teeth is less with ultrasonic machining.

The sample prepared by mechanical mixing method has large microstructure with serious agglomeration of grains with the same composition.
Since the number of the internal secondary electrons generated increased with Ep, secondary emission yield (δ) also increased with Ep.
Therefore, it could be deduced that RE2O3-Mo cathode with nano-sized grains is expected to exhibit high secondary emission property.
For the effective SEE cathodes with a δ more than 2.0, the number of emitted secondary electrons exceeds the number of primary electron.

The test statistics is computed using the form , (3) where is i-th observed value of dependent variable, i-th estimated value of dependent variable using the regression model, mean of the dependent variable, number of independent variables and number of observations.
According to the type of transported materials, the conveyor belts are classified as belts of class 2 (grain size between 50 and 100 mm, moderate bulk weight) and 3 (grain size between 150 and 400 mm, sorted material, high bulk weight).
Malindžák, Number of conveyor belts optimization regarding to its type and logistical parameters in mining industry, Acta Montanistica Slovaca 4 (2008) 524-531.

Fig. 1 Effect of Na2SiF6 on setting time at W/C 0.26 Fig. 2 Effect of Na2SiF6 on setting time at W/C 0.5 There are a large number of OH- generated during the process of hydration.
In the case of low content, the formation of the insoluble CaF2 grains is small and specific surface area is very large, and it is easy to adsorb on the surface of clinker, which hinders the process of hydration, so the setting time is delayed; In the case of high content, increasing of F- concentration will accelerate the dissolution of Ca2+, so as to promote the dissolution of silicate, the macro is shown to reduce the setting time.
During the process of hydration, due to the dissolution of silicate is not consistent, the silicon-rich layer is formed on the surface of the grain, which forms negative electric double-layer structure, so the cement-water system has obvious colloidal property[8].
It can be seen from the graph that there are a large number of non-hydrated clinkers aggregate in the cement slurry with 2%-FN, Afts like the needle can be observed in the blank sample and the sample with 5%-FN.
Study on the effect and mechanism of fluorosilicate on concrete[J], Concrete, Number 5 in 2015 [3] Zhang Tiemin, Wang Lijiu.

For each column, small angle grain boundaries can be clearly observed.
The mechanism of the dislocation reduction is that during the initial stage, three-dimensional grain islands were deposited and subsequently smaller grains were incorporated into bigger grains resulting in much larger grains.
Simultaneously, dislocations were filtered or bent during grain incorporation.
For Tg = 1100[ oC], grain-like defects caused by small-angle grain boundaries were enhanced to become asperities.
In contrast, for Tg = 1600 [ o C], undistorted atomic steps were observed, and the number of pits was much lower than that for Tg = 1400 [ oC].

The simulation results show that, while the magnitude of pre-stress is controlled in a certatin range, the number of radial cracks reduce as the increasing of pre-stress magnitude, contray to the transverse cracks.
For the discrete element model which can simulate the structrue of granite, different size particles are generated and tightly-packed by PFC2D software, then the structure of granite is simulated by finding adjacent particles to form “cluster” (set the maximum number of particles concluded in cluster).
As is shown in Fig. 5, the increase in pre-stress cause the number of cracks to decrease, which explains that the damage of machined surface were reduced.
All the above simulation results show that pre-stressed machining can change the propagation law of cracks, improve quality of machined surface, and reduce the number of cracks obviously; meanwhile, the increase in pre-stress will not increase the cutting difficulty.
Fig. 5 Cracks number vs. pre-stress Fig. 6 Cutting force vs. pre-stress 4.

Both applications add a large number of interfaces to a bonded-particle model representation of the rock.
Fig.1 Peak strength of tri-axial compression test Laboratory results Calibration with PFC In PFC, the BPM (bonded particle model) mimics the mechanical behavior of a collection of grains joined by cements.
The simulation of marble sample including 5 step process: (1) compact initial vessel; (2)install specified isotropic stress; (3)reduce the number of “floating” particles;(4)install particle bond;(5)remove from material vessel.
Table 1 Calibrated model Micro-properties for marble with tri-axial compression test results property value Grains Rmin [mm] 0.75 Dmax/Dmin 1.66 r [kg/m3] 2700 Ec [GPa] 40 kn/ks 2.5 m 1.0 Cement l 1 Ec [GPa] 40 Kn/ks 2.5 sc [MPa] 100±23 tc [MPa] 200±46 Typical cracking of different confining pressure are shown in Fig. 2 for the PFC2D marble model with the minimum particle diameter of 1.50 mm.
From Fig.2, we can draw a conclusion that the crack number increased with the increase of confining pressure.

Lime rock reduced stone of continuous grain composition of Weifang, have a grade 5mm-20mm, sediment percentage 0.39%, air dry, native rock strength 55.6±8.9Mpa, apparent density ρoa=2.669g/cm3 , stacking density ＝1560 Kg/m3 .
The grain composition of yellow river sand meets the necessity of JGJ53-92.
Table 2 Different mixing ratio and cube strength of concrete at different age number Different material quantity /kg C FA W S G FTP cement fly ash water fine coarse admixture A0 530 0 160 690 1080 6 A1 477 53 160 690 1080 6 A2 424 106 160 690 1080 6 A3 371 159 160 690 1080 6 In order to validate the influence of fly ash on concrete performance, C30 concrete as a example, fly ash admixture respectively dosage of cement is 0%, 10%, 20%, 30% , mainly landslide degree and permeability of concrete is shown in table 3.
Table 3 Landslide degree and permeability of concrete number fly ash% permeablity degree (mm) landslide degree (cm) cohesiveness water-retaining property slump changes (cm) 0.5h 1h 2h A0 0 6.1 20.5 good ordinary 18.4 14.2 8.6 A1 10 5.8 22.1 good good 21.8 20.5 20.1 A2 20 5.3 23.8 good good 23.1 22.8 21.7 A3 30 6.9 24.6 good good 24.5 23.9 23.6 As fly ash replacement ratio increases gradually, concrete slump is gradually increasing.
Table 4 Influence of fly ash content on the concrete mechanical property number fly ash% Concrete compressivestrength(MPa) 3d 7d 28d A0 0 18.4 32.2 36.8 A1 10 18.2 33.1 38.1 A2 20 17.6 32.9 38.6 A3 30 16.5 25.4 35.2 Engineering Application The third-phase fortune plaza project of Wei fang has a gross building area approximately 5300m3.