Search results

Silicon carbide grain composition (weight ratio) respectively is (1.0-0.5mm) 50%, (0.5-0.1mm) 17%, (5-45μm) 20%, (1-5μm) 13%.
Table 1 Additives in the experiment Number Additive Purity (%) d50 (μm) 1 silica fume >90 17.65 2 quartz >96 18.87 3 alumina >98.6 4.863 4 aluminum powder >94 27.8 Sample Preparation.
Silicon carbide grain and additive were mixed for 30min by mixing machine.

Introduction Thixoforming of aluminium alloys is state of the art and a growing number of serial production lines can be seen.
Even known Fig. 4 predicted a fully solid structure, some liquid phase shows up in dark at grains boundaries, on the right hand side of Fig. 5.
Nice globular grains with entrapped liquid are also to be noticed.

But a tiny decrease occurred on the curve when the temperature reaches 1200 oC, which could attribute to a number of factors, such as the phase constitutes, the grain size, and the lattice defect et al. [14].
Generally, the Qxf value is dependent on the extrinsic factors such as density, secondary phase, impurity and grain size, along with the intrinsic factors [18].

In the engineering journals, such as Annals of the CIRP, Applied Mechanics and Materials, Manufacturing Engineering, Transactions of the ASME - Journal of Manufacturing Science and Engineering Journal of Materials Processing and Technology, can be found a large number of articles concerning to ultrasonic welding, which highlights the research timeliness in this field.
Microstructural analyze Copper samples have the structure consisting in Cu-α solid solution, with equiaxed grains oriented on the lamination direction.
The influence of diferent working regimes on copper ultrasonically welded surfaces In the welded nucleus (N) the welded structure aspect is modified regarding the orientation (distorted) and the grain size (larger and finer).

Using these fluxes can both reduce the need for the edge preparations and increase the productivity because of the reduction in the number of weld passes required to make the joint.
The microstructure of the melted material is essentially formed of austenite with discontinuous skeletal δ-ferrite in the grain boundaries, as illustrated in Fig. 2.
Compared with the center of TIG weld, the fluxes provide a small refinement to the grain microstructure, which is probably because of the fact that A-TIG welding increases the weld penetration, obtaining a faster cooling speed and thus shortening the holding time of weld metal, thereby affecting the formation of the metallurgical microstructure of its weld beam.

For the fit of S-N curves covering the whole range of the number of cycles to fracture were used two regression functions: the Stromeyer and Kohout + Vechet function [7], where a, b, B, C and σ∞ are parameters determined in regression calculations.
However, three similar features were found in all cases of measurement: uniform growth and distribution of small sub-grain cracks and slip plane formation (high activity), the growth of these microcracks across the grain boundaries and crack nucleation and incubation (low activity) and final coalescence of these cracks into localized main crack and the stable and unstable main crack propagation (high activity).

This is because with the increase of linear velocity of grinding wheel, the number of abrasive in area of grinding per unit time increased, resulting in a decline in the cutting force of the single particles, leaving the workpiece surface grinding scratches weakened.
Fig. 4 The influence law of grinding wheel peripheral velocity of the surface roughness 5.3 The relationship between grinding force and grinding depth in Cylindrical ELID grinding When different particle sizes of cast iron-bonded diamond grinding wheel are used in the ELID grinding experiments,the grinding force is increased with increasing depth of the grinding.What is more,at the same cutting depth,the smaller the particle size of the abrasive particle are,the larger wheel grinding force is.The reason for this phenomenon is that the space of micro-grained grinding wheel between two consecutive Grinding Blade is small,such that a single grinding blade cutting depth is small.
L Further, since micro-grained wheel protrusion height and minimal chip space are small, which cause the outflow of abrasive dust is not smooth,it will increase the difficulty of cutting edge micro-grinding into the workpiece, it will also lead to grinding force increasing. 6 Conclusions It can get the following conclusion, through experimental study on the technological renovation of machine tools and ELID precision grinding experiment research

(Right) The total heat flux qt can be estimated from the equation: qt=qw+qs+qch+qf (2) where qw, qs, qch, qf represents the heat flux convected into the workpiece, wheel, chips and coolant respectively, and qt can be obtained by another equation: qt=ec∙vw∙aplc (3) where lc is the contact length. qw can be calculated by the following equation: qw=qt∙ε (4) Meanwhile, a ‘workpiece-wheel’ partition ratio Rws is defined as: Rws=qwqw+qs=1+0.97kgβw∙r0∙vs-1 (5) where kg is the thermal conductivity of CBN grain (1300W/m∙K in this study), βw represents the thermal property of workpiece, i.e., 14.7 W/m∙K in this work, r0 means the effective radius of grains, it is taken to be 10μm in the investigation.
Besides, qf can be estimated as[6]: qf=[min⁡(T,120)-T0]∙hf (6) where T0 is ambient temperature, which is evaluated as 20, T is the measured temperature，and 120 means the film boiling temperature of grinding fluid. hf represents the heat transfer coefficient of water-based fluid, which can be calculated as: hf=Nu∙klc (7) where Nu is nusselt number of flow, k is thermal conductivity of the coolant.

The algorithm can decrease the synchronization hop count by constructing a spanning tree, and uses two-way SRS in inter-cluster and one-way ROS in intra-cluster to reduce the number of messages required for the network synchronization.
Figure 2 reflects changing trend of the algorithms‘ mean synchronization error as the increasing of the nodes number.
Fig.2 WSN Error’s changing trend Conclusion For the problem that classical time synchronization algorithms existing in large-scale WSN, this paper have proposed a time synchronization algorithm based on cluster-tree that constructs a spanning tree to effectively reduce synchronization hop count, and uses two-way SRS in inter-cluster and one-way ROS in intra-cluster to reduce the number of messages required for the network synchronization.
Fine-grained network time synchronization using reference broadcasts [J].

Solar power research primarily focuses on studying fine-grained materials with a perfect spherical shape but natural and manufactured granular materials are typically irregular in shape.
Coordination number and RDF analyses.
Their minimum coordination number is around 3, while spherical particles can have a minimum of 2.
In contrast, spherical particles' curve is left-skewed, peaking at a coordination number of 6.
(a) Distribution of coordination number and (b) RDF for all samples.