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Orthogonal experiment method was adopted in this study to simplify the experiments of lead-free wave soldering and optimize the process parameters in order to achieve the excellent quality and properties.
In contrast to other methodologies, which use mostly one-factor-at-a-time studies to identify controllable parameters, in this study the effects of four main factors were studied through the method of L9 (34) orthogonal experiment.
A standard orthogonal array matrix L9 (34) was constructed with four major production factors (Table 1).
In Table 1, the factors are A (1) , A (2) ,…,A(k) , and the levels of the factors are n1, n2, …, nk.
An n×n pairwise comparison matrix, A, is thus generate and exhibit two clear properties: (i) Homogeneity: if elements i and j are considered equally important, then aij=aij=1.

Significance of factors and their interactions can be computed using statistical analysis.
Important mechanical and thermal characteristics are.
Result and Discussion In this study A (spindle speed), B(feed rate),C(axial depth of cut) are the main factors considered for the experiment of surface roughness, and also cross effect of three factors are considered to get the quadratic relation.
The magnitude of B2 also affects surface roughness, other factors do not make big effect to surface roughness.
The influence of spindle speed, feed rate and depth of cut affecting on the surface roughness was found by ANOVA.

Based on the engineering properties of red sandstone, especially hydraulic mechanical properties, red sandstone slopes are taken as examples.
Several examples of slopes reinforcement projects of Changji highway in Hunan province are taken for the analysis of red sandstone rock properties deeply.
Red sandstone’s Properties in West Hunan Geological Mineral Characteristics.
Zhihong Lin [6] considered that the infiltrating softening properties of red sandstone are controlled by the content of clay mineral content, especially the content of montmorillonite which has a hydrophilic property.
Fig. 2 X ray diffraction spectrum of red sandstone from Changji highway Fig. 3 Four red sandstone samples under polarizing microscope Macro-mechanisms of Landslides Due to the diversity and complexity of slope structure and influence factors, landslides types and mechanism are diverse and complex.

This method is used to study the fracture characteristics of concrete and measure the stress intensity factor of I type crack tip.
Material properties of concrete are greatly improved and load bearing conditions are more complex [1].
For example, the method has the requirement of surface features and illumination because of correlation calculation of intensity distribution; Correlation calculation is implemented through transition of subregion and affected by rigid body rotation.
In this paper, the method is introduced to study fracture characteristics of concrete and used to measure I type crack tip stress intensity factor of concrete.
Displacements of crack tip can be obtained by white light digital image analysis in frequency domain and stress intensity factor IK can be calculated.

However due to the randomness of all these properties, the fatigue crack growth (FCG) is a process that is naturally considered to be random [5] and requires appropriate inspection plan in order to prevent the risk of failure and improve maintenance strategies.
The fracture can be described by the use of the stress intensity factors in various modes.
Three factors a0, C and ac (or ad), presented in table 1 are considered, each at three levels (eq min, max and middle values ) where 27 run simulations has been conducted using general full factorial DoE.
Crack size (m) Fig.4: a=f(N) deterministic case Fig.5: a=f(N) random case Referring to the figures above, for a target critical crack length a very significant scattering of the life cycles is observed, hence the necessity to take into account the uncertain parameters affecting the propagation.
[33] Parks MD: A stiffness derivative finite element technique of crack tip stress intensity factors.

Simulation results show that the stress, strain and temperature distribution within the sample is uneven, uneven distribution affect the organization, and with the changes in the deformation process and calculation results with the experimental data exactly.
The finite element method can be used in the actual production forecast after tissue deformation components, optimization of process parameters to control the quality of the finished piece. 1 Introduction Metal temperature of various parts of the work piece and tooling, different stress during hot deformation, and microstructural evolution during deformation is closely associated with these factors.
The thermal deformation of metal deformation, thermal power conversion factor of 0.9.
Numerical Simulation of Coupled Thermo－Mechanical Behavior of a Cylinder Billet During Hot-forging Process.
[4] XIA SHAN-mu, Li DA-yong. the mechanical properties of cast iron for fast prediction of artificial neural networks, Applied Sciences, 2002,20 (3) :309-312

Predictor equations for crater radius and depth incorporating the significant factors were developed and also validated with the experimental results. 1.
Recent advancements in the process have shown that addition of metal powder particles in the dielectric fluid may significantly affect the properties of the machined surface as well as affect the material removal rate (MRR) and surface roughness (SR).
Pulse duration, power and size of plasma channel radius, including its growth were identified as significant factors affecting the size of the crater.
The model was created with a domain of 0.5×0.5×0.25 mm for H11 die steel material having properties as listed in Table 1.
Predictor equations for crater radius and depth incorporating the significant factors were developed and validated with the experimental results.

The physical-mechanical properties of chromium coatings from low-concentrated electrolytes with additions of organic substances were studied when comparing with similar ones from standard sulphate electrolyte.
It has been established that the properties of chromium coatings from low concentrated electrolytes are superior to those of standard sulphate electrolyte.
The physical-mechanical properties of chromium coatings depend on the composition, temperature of electrolytes, the concentration of organic additives, the current modes of chromium deposition under constant current, pulsed or reverse deposition in a low-concentration electrolyte [3-6].
Absorption spectra with CrO3 solutions containing CV in the temperature range from 20 to 60 ° C have no differences, i.e. a change in temperature in this range does not affect the working properties of the additives.
Current density of 70 A / dm2 and temperature of 70 ° C with chromium deposit thickness of 20 μm from a low-concentration electrolyte (1.5 g / l H2SO4 + 150 g / l CrO3 + 1 g / l CV) were taken as planning factors.

Researches on Structural Factor Involvement in Oral Tribology Stela Carmen Hanganu1,a, Lucian Constantin Hanganu2,b, Georgiana Macovei1,c, Georgeta Lidia Potop 3,d, Stefan Grigoras2,e, Florin Tudose Sandu-Ville2,f, Adina Oana Armencia1,g 1Gr.
X-ray diffraction on crystals [3] In order to establish the structural factor involvement in oral tribology, the experimental researches were focused on the two dental restorative ceramic materials mentioned above.
In general, the mechanical properties of a material are closely related to the crystal size, the interface topology, the presence of micro-cracks and pores and surface texture.
Vizureanu, Tribological comparative study on two composite materials for restorative dental applications in smoking affected teeth, Materiale Plastice (Bucharest), (47) 3, (2010) 375-378
Hanganu, Evaluation of Mechanical Properties by Stereo-and Scanning Electron Microscopy of Some Heat Curing Dental Resins, Materiale Plastice (Bucharest), (47) 2, (2010) 375-380.

In this context, previous studies [18]–[20] investigated the effects of other factors, such as w/c ratio, aggregate size, and volume of coarse aggregate on the behavior of a conventional concrete mixture.
The findings showed that increasing the aggregate size to 20 mm, decreased the fresh properties and enhanced the SCC’s mechanical properties.
It was found that the fresh properties were increased, and the mechanical properties decreased with the ratio of w/p in the SCC.
Furthermore, the performance of SCC was investigated in order of fresh concrete properties and mechanical properties.
Xie, “Mechanical and durability properties of recycled aggregate concrete: effect of recycled aggregate properties and content,” J.