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Using lasers to clean and dress grinding wheels has been investigated by a number of groups around the world over the past three decades.
The dressing process has also to remove bond material and either remove blunt cutting grains or fracture them to create new cutting faces.
A new class of high brightness laser systems has been developed by a number of laser companies that hold the promise of laser micromachining structures at higher speeds, and thus could be viable for the laser cleaning operation.
Figure 2 Optical micrographs of laser cleaned aluminium oxide ball wheel The work-piece material can be seen as dark filaments winding round the aluminium oxide grains.

The thermal shock properties of materials depend on large number of parameters, e.g. tensile strength, fracture toughness, Young’s modulus and thermal expansion coefficients.
Compared to the Hasselman quench-strength method [12], the evaluation procedure is simple, the sample preparation is easy and only a small number of samples are needed for a series of measurements at different temperatures.
The microstructure of the sintered composites consisted mainly of elongated b-Si3N4 grains (several micrometers in length), equaixed b-Si3N4 grains, hBN particles and intergranular phase.

Laser cladding is an important statement and modification techniques, has been a large number of applications[4] in the industrial field.
Smaller laser bath containing a small amount of high-melting nanoparticles convection and heat and mass transfer effects on melt compared to higher levels, organizations are more conducive to the formation of alloy solidification compounds, while nanoparticles solidification crystallization front impede dendrites grow fine grain and raise as heterogeneous nucleation resulting enhanced nucleation rate is also conducive to improved wear resistance[5].
Figure 1 Metallographs of laser cladding different nano-Al2O3 content The nano-Al2O3 powder by 0%, 1%, 2% and 3% (by mass) of the added amount of Ni-base alloy powder in an agate mortar were thoroughly mixed, and the sample powder mixed in turn mark number: Ni-base, Ni1, Ni2 and Ni3.
Improve coating hardness and dry sliding wear resistance performance improvement is believed to be a small compound with a more dispersed in the coating formed on; Laser bath containing a small amount of high-melting nanoparticles melt convection smaller and heat and mass transfer effects compared to higher levels of the organization are more conducive to the formation of alloy solidification compounds; while solidifying crystalline nanoparticles hinder the forefront of dendrite growth and improved as heterogeneous nucleation nucleation produce fine grain rate enhancement also help to improve the wear resistance.

The number of it is very large in Heilongjiang Province coal cities, in Jixi City, for example, the storing up of coal gangue are nearly one hundred million tons, and increased at the rate of about 8.5 million tons every year.
Third, efforts are made to improve the legal system and regulatory mechanisms based on the existing conditions of the Heilongjiang Province and achieve the sustainable development strategy of coal urban living environment fundamentally. 4.2 Control the direction of coal urban industrial development In Heilongjiang coal cities, not only the presence of a large state-owned coal mines, there are a large number of coal enterprises as well.
First, the slope collapse area formed renovation, puddles turned into the aquarium, sloping tree-planting or planting crops to establish breeding industry, feed mills, to form a complete food chain engineering systems; Second, restoring Green ecological restoration planting, forest complex grass, in a certain range of living, strengthen the construction of plant habitats; Finally, make the use of coal gangue the generation or grain mill brickmaking it turning waste into treasure, not only can make the use of waste and energy savings, but also can greatly reduce the area of cultivated land occupied and effectively alleviate the air pollution. 5 Conclusion The three main themes of the 21st century is the population, resources and environment.
Heilongjiang as a province rich in resource, is not only in terms of coal resources, but also in timber, grain, oil and other national development necessary resources.

As shown in Figure 3 (a), the grains of the raw materials are unevenly distributed, and the micro structure is continuous.
The results show that horizontal wedge rolling can significantly improve the grains, but the risk of central Damage should be considered.
Figure 6 (C) shows that macro -Damage has obvious cross -shaped characteristics, and there are a large number of shear cracks in the field of pore aggregates.
With the growth and convergence of micropores, such as enlarged images, a large number of crack distribution at the tip of the tip is damaged, which further illustrates the cracking of the metal matrix before the microphone gathering.

Front of the large number of applications of the mullite mineral, many researchers seek to synthesize it from the mixture of Al2O3 and SiO2 powders, or from aluminossilicates, such as smectite.
Introduction Due to the excellent properties and the large number of applications of mineral mullite, researches related to the obtaining this material have achieve more and more importance.
The impurities, when in solution and in contact with the crystalline structure of mullite, lowers the surface energy in some crystal directions, inducing to a preferential growth in other directions, resulting in the formation of elongated grains.

A significant number of micro-pores were present in the melted layer for AA2124 treated with high number of laser pulses, leading to the decrease of the corrosion resistance. 1 Introduction Aluminium alloys possess good corrosion resistance for most environmental exposures due to the natural oxide film on the surface.
The effect of the applied number of laser pulses per unit area is also considered. 2 Experimental The nominal compositions of the investigated commercial aluminium alloys AA2124-T4 and AA6061-T4 are given in Table 1.
The number of laser pulses per unit area increased from 10 (10P) to 25 (25P), and 40 (40P), and the frequency was constant at 10 Hz.
Undissolved Al2CuMg (S-phase) and Al2Cu (q-phase) in solution treatment, which were preferentially located at the grain boundaries, were also found in the alloy.
The melted depth increased with increasing number of laser pulses for both alloys, which is believed to be due to the repeat of the melting process with multi number of laser pulses.

Every cell in the grid system will be assigned a random number (0-1) and the cell whose random number less than will be selected as a core.
(vi) A new random number will be assigned to neighboring cells of each growing pores.
The neighboring cell in direction will become part of macro pore if its random number no greater than.
Considering the computational time and numerical stability, the grid number of the 2D computational domain is set to be.
(3) where is the local non-dimensional relaxation time, which is equal to in solid (grains) phase and in the gas (pore) phase respectively.

Additionally, optimization of the number of nodes to minimize the CPU memory consumption is necessary, owing to the large number required in laser heating simulation.
Dimensions of the sample were 0.75×0.45×0.35 mm3 which is large enough for the temperature to achieve the steady estate, at the values of scan speed applied, and, conversely, lower than the characteristic size of the mineral grains (in the order of 0.5 mm to 2 mm) Time steps used were different during the heating, Dt = 5 ns, and the cooling (Dt depending on the repetition frequency f), owing to the characteristics of the pulsed laser treatment.
FEM simulation features FEM Simulation Features Sample dimensions 0.75×0.45×0.35 [mm3] Mesh sizes 30, 15, 5 and 1[µm] Elements distribution (XYZ): 130×70×15 Total number of elements: 136500 Total number of nodes: 148816 Number of pulses 50 Time step (heating): 25 ns Time step (cooling): Depending on f In order to obtain a first estimative of the heat diffusion towards the bulk, the temperature at the center of the laser spot was obtained.
In the case of a number of pulses, however, a time is required for every point of the sample to achieve the steady state, owing that the temperature in the centre of the spot, and of the sample, has not returned to the initial value before irradiation with subsequent pulse.
Evolution of the maximum temperature reached after a number of pulses a), and temperature variation as a function of time in the centre of the surface, b).

Table 3.1, The original sections representative deflection value and resilience modulus Pile number Representative deflection (0.01mm) The old road top modulus (MPa) Top surface soil modulus (MPa) 20 cm bottom modulus (MPa) K0+000~k1+000 156.45 98.53 23 48.18 K1+000~k2+000 135.63 120.92 32 61.64 K2+000~k3+000 105.01 156.19 53 87.40 K3+000~K4+000 148.50 110.44 27 54.81 K4+000~K5+000 157.74 103.97 25 51.32 K5+000~K6+000 153.25 94.67 20 44.89 Cool regeneration of the cement stabilized of base course design results The pavement adopt cement stabilized cool regeneration technology.
Construction method used in the process of sand filling real-time detection of compaction, some random shown in table 3.5 situation, accord with compaction degree requirements Table 3.5 Part of random compaction degree Sampling pile number Water content (﹪) Dry density Compaction degree Sampling pile number Water content Dry density Compaction degree K1+220 4.1 2.306 99 K3+920 3.8 2.282 98 K1+560 3.9 2.168 93 K4+680 3.5 2.296 98 K2+150 3.6 2.304 99 K5+260 3.6 2.224 95 K2+900 3.5 2.283 98 K5+570 3.9 2.187 94 K3+305 3.4 2.213 95 K5+960 5.0 2.181 93 The unconfined compressive strength sampling conditions of base course： The construction process of cold regeneration of the base course seven days to cement the unconfined compressive strength with according to the highway engineering inorganic material test procedures in feeding stable T0805-94 methods of random situation. table 3.6 shown.
Table 3.6 7 days the unconfined compressive strength of sampling Construction pile number Number of parts coefficient Cv (%) Average compressive strength(MPa) Represent value Rc-1.282S K0+000~K1+160 6 6.0 3.19 2.95 K3+160~K4+005 6 15.3 3.43 2.76 K4+560~K5+580 9 11.7 3.34 2.84 During the construction of got cold regeneration of cement on-site ,sampling test ,got eight points altogether ,core samples close-grained and hole wall smooth ,core sample length comply with the design requirements.
After all sections regimen use 5.4m Beckman beam deflection situation instrument measuring pavement deflection shown in the table 3.7 Table 3.7 Deflection testing situation Sections pile number Point number average (0.01mm) Three-parameter stress-life (0.01mm) Representative deflection (0.01mm) K0+000~k1+000 100 24.07 18.39 51.66 K1+000~k2+000 100 30.48 10.71 46.55 K2+000~k3+000 100 25.68 12.41 44.29 K3+000~k4+000 100 27.69 11.58 45.06 K4+000~k5+000 100 25.72 9.96 40.66 K5+000~k6+000 100 27.84 9.28 41.76 Conclusion (1)Make full use of the original rood miller disused material plane ,and avoid waste material covering ,having use to protect the ecological environment ,At the same time saving a lot of building materials ,both saved the resources ,and reduce the investment and reduce the cost (2)The old road that add a store the base course is highway maintenance traditional treatment ,this leads to continuously improve road elevation make more and more narrow road width ,and lap with