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So that it is very important to study the resistance to crack initiation properties of HDPE pipe and its butt-fusion welded joint.
Fracture properties can be expected to be governed primarily by the degree of crystalline, even though this parameter is just one of the many factors which characterize the semi-crystalline state.
So the degree of crystalline is thus the first structural variable that to be related to fracture properties at different zone of butt-fusion joint.
At the same time for polymer material, the degree of crystalline decides its mechanical property.
The test of basis mechanical property shows the same results.

Crystallization within pores modifies the microstructure and transport properties of the host medium and can induce mechanical damage through crystallization pressure, leading to deterioration.
This explains why, in the early stages, porosity decreases while mechanical properties initially improve [7-10].
In spite of the missing information on the subflorescence properties (mean pore size, porosity, etc), the conclusion is therefore that the heave stops not because of a mechanical effect but because of capillary effects [26].
The bead size has probably an impact on the subflorescence properties.
Ben Nasrallah, Porous medium coffee ring effect and other factors affecting the first crystallisation time of sodium chloride at the surface of a drying porous medium, Physics of Fluids 25(12), 127101 (2013)

The nature, mechanical characteristic and other properties of the base metals introduce also certain requirements for the FSW equipment, because FSW is a mechanical process.
Other important factors are also taken into account: sizes and positioning of the sheets (up or down), rolling direction of the sheets, room temperature, temperature of the sheets, material and temperature of the support plate.
The nature, mechanical characteristic and other properties of the base metals introduce also certain requirements for the FSW equipment, because FSW is a mechanical process.
Main technical characteristics of the FSW equipment Number Technical characteristics of the motor for the tool rotary motion Experiments no. 1 - 4 Experiment no. 5 [5] 1 Rotational speed n [rev / min] 800 – 1,200 200 - 400 2 Rotation direction clockwise and anticlockwise 3 Mechanical power PMrot [kW] 2.98 - 3.62 2.87 - 7.25 4 (Drive) Torque Mrot [Nm] 26.43 - 35.58 92.00 - 230.10 Factors that Influence the FSW Process Other important factors [1, 6 – 11] are also taken into account: sizes and positioning of the sheets (up or down), the rolling direction of the sheets, room temperature, temperature of the sheets, material and temperature of the support plate.
Sorensen1 (1Brigham Young University, Provo, UT, USA); 1Ben Nelson and 1Sam Sanderson: ”Properties and Structure of Friction Stir Welded Alloy 718”.

For example, in the mechanical field, it can be used to detect microscopic morphology of the surface of ultra-precision machining.
In the field of micro-electromechanical systems, it can be applied to the detection of micro-mechanical adhesion between the components.
In operation, the probe tip and the sample contact surface of the holder registration state, and the tip geometry morphology are important factors affecting the image resolution.
Thus tip wear will not only reduce the quality of imaging, but also bring artifacts, seriously affecting the subsequent data analysis.
The working principle of the atomic force microscope and Nano-contact force calculation model The working principle of the atomic force microscope is shown in Figure 1, which is fixed with one end, fitted to the tip of the other end of the weak biasing force of the resilient cantilever, which is very sensitive to the test sample surface topography or other surface properties.

Most of these materials, however, are very hard and brittle, and their properties are easily affected by the impudent surface damage caused by the finishing operations.
The generation and propagation is greatly affected by surface energy of a material cut.
Estimation of Surface Mechanical Characteristics Since machining is always carried on a surface or surface layer of material, a mechanical characteristic of surface or surface layer is more important on the cutting process than that of majority.
And the mechanical characteristic are discussed.
The dimension factor of the distribution becomes very large.

L18 orthogonal array with factors and response Exp.
The most significant factor affecting the precision and accuracy of the high speed EDM process have been identified as factor A (current ),factor C (pulse on time),factor D (Dielectric pressure) account for concerning the (33.59,23.59 and 16.93 )% at the method variance.
“Microstructure and mechanical properties of silicon nitride–titanium nitride composites prepared by spark plasma sintering”.
“Densification and Mechanical Properties of Electro conductive Si3N4 -Based Composites Prepared by Spark Plasma Sintering” Sains Malaysians 41(8): 1005–1009
“Properties of Si3N4–TiN composites fabricated by spark plasma sintering by using a mixture of Si3N4 and Ti powders”.

Some steps, avoiding clay being carried into the shaking feeder by rubbles, and installing dust collector devices, etc, can reduce the content of 0.075mm particles in aggregates. 2.3 Control the Content of Elongated and Flaky Particles The producing of elongated and flaky particles is effected to the characteristics of mineral aggregate, mechanical properties, processing technology and so on.
Three factors here affected the ability of vibrating screen, including the exciting force of oscillating screen, the inclination angle of oscillating screen and the changing aggregate flows.
The important factors affecting the above process are weighing accuracy of electronic scale and the “carry-over”.
The weighing accuracy of asphalt is an important factor that affects the quality of asphalt mixtures.
The influence factors,s analysis of weighing precision for batch asphalt mixing plant, Highways & Transportation in Inner Mongolia, 78(1), P17-18, 2003

The tool material should be matched with workpiece material from physical, mechanical and chemical properties.
Analyzing the influence factors and their contributions is useful to obtain the required surface integrity [6].
Also, work hardening will reduce the surface quality and affect the fatigue strength.
The wear reasons are complex for the mechanical, physical and chemical factors [7,8].
Ashley: Mechanical Engineering (1995), p.

At elevated temperatures, the mechanical properties will change with yield strength decreasing and the material deformation behavior from brittle to ductile, resulting in reducing tool wear, improving surface finish and increasing material removal rates.[1-3].
The finite element simulation method is a powerful tool for simulation the damage of engineering material, which can help to analyze the main factors of causing the damage, understand the law of fracture and find the way to avoid cracks.
The crack size, loading stress and fracture toughness are three key factors influencing the edge damage for brittle materials at room temperature.
Fig.1 Schematic diagram of the mechanical properties and temperature for silicon nitride[96] Yang et al. [6] demonstrated that the mechanisms of the elevated temperature on edge chipping include softening and toughening.
a ) Top width of edge chipping b) Critical mechanical energy release rate Fig.7 Effects of operating parameters on edge chippings The width and length of edge chipping can’t be accurately predicted due to excessive and uncertain fracture factors.

Cross-linked polyethylene is widely used as electrical insulation because of its excellent electrical properties such as low dielectric constant, low dielectric loss and also due to its excellent chemical resistance and mechanical flexibility.
The electrical properties of an insulator are affected by the presence of cavities within the insulating material, in particular with regard to theelectric field and potential distributions.
For example, polyethylene exhibitsexcellent electrical properties and is used for cable insulation.
Compared to PE, it also has better ageing characteristics and higher resistance to water treeing.Due to these properties, XLPE has become the most common insulation used for the high voltagecables [9].
Properties XLPE Cable PVC Cable EPR Cable Dielectric constant 2.3 4.5-9 3 Dielectric strength(kV/mm) 20 15-20 15-20 Resistivity(Ω.cm) 1x1016 1x1013 1x1015 Dissipation factor <0.03 0.01-0.02 0.16-0.3 Thermal conductivityW/(m.K) 0.38 0.19 0.48 X Y Z Fig. 5Comparison of the electric field along the radial line for the case of EPR, PVC, and XLPEinsulating materials.