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This is made to ensure that the flow at the inlet section of the duct is not affected significantly by the sudden expansion in the geometry at the step and the flow at the exit section becomes fully developed.
These contours show that the affecting zone of thermophoretic force is reducing while the Reynolds number is increasing and this can cause decreasing the chance of particles for deposition on the cold wall.
It is gained from this Fig that radiation effect can be negligible which is due to low radiative properties of air such as absorption coefficient, Table ΙΙ.
Physical properties of particles (silicon dioxide) Density (kg/m3) 2220.0 Specific heat (J/kg K) 745.0 Thermal conductivity (W/mK) 1.38 TABLE II.
Air properties Density (kg/m3) 0.8711 Specific heat (J/kg K) 1014 Thermal conductivity (W/mK) 0.0338 Prandtl Number 0.1 Absorption coefficient (1/m) 0.7 Albedo coefficient 0.5 References [1] N.

Hot incentives include ultrasound, flash, mechanical vibration and electromagnetic, etc.
Due to many influence factors, new detection methods (e.g.acoustic emission technology, metal magnetic memory method are still not mature enough to be practically applied.
The purpose is to study the temperature features of the weld surface crack under eddy current heated, the impact of following factors on the temperature field distribution are numerical analyzed: a) orientation θ; b)excitation frequency f; c)crack length; d)crack depth; e) crack width.
The physical properties of all materials are listed in the Table 1.
Table 1 Material properties Properties Value Unit Structural Steel Copper Air Heat capacity 475 385 1.005 [J/(kg*K)] Density 7850 8700 1.205 [kg/m3] Thermal Conductivity 44.5 400 0.0257 [W/(m*K)] Relative permeability 200 1 1 [1] Electrical Conductivity 4.032×106 5.998×107 0 [S/m] Numerical analysis.

It is well known that the properties of such material are directly influenced by its structure which can be affected by several factors, including additive composition, physical parameters and the thermal process responsible for its preparation.
This promotes a reduction in water absorption and an increase in mechanical strength.
In this paper we present the results of our study and discuss the influence of such important parameters as the clay to ash ratio, and the sintering temperature on the technological properties like the bulk density, porosity, and the firing shrinkage.
This behaviour suggests that the existence of unburned carbon left in the ash is responsible for increasing the porosity, and this is one of the main factors that influence the decrease in bulk density.
Properties and Application (A review)”, Glass and Ceramic, vol. 60, no. 9 – 10, pp. 280 – 283, 2003

Precise Angle Control of Electromechanical Actuator With Fuzzy PID and Genetic Algorithm Yebing Cui1, a, Jian Zheng1,b , Yutao JU 1,c , and Jing Xu1,d 1 School of Mechanical Engineering Nanjing University of science & technology, Nanjing, China acuiyebing@163.com, b,c juyutao@mail.njust.edu.cn email, druole@163.com Keywords: electromechanical actuator;　Brushless DC motors;　genetic algorithm;　fuzzy logic Abstract.
These properties include the mechanical resonance effect, the delay issue between the control signal and the actuator, the motor parameters, the battery voltage drop and the variable friction effect among the gears mechanism.
In practical applications, the controller’s effectiveness is directly affected by the different combination of the three parameters kp, ki , kd, Also the optimization of the traditional PID requires certain experience, and many methods’ optimization results are not ideal[10].
Although the fuzzy PID controller combines the advantage of the two controllers, there are some unfavorable conditions to realize intelligent control, such as control rules of the fuzzy inference system is uneasy to formulate, and the fuzzy quantitative factor and PID scaling factor also are determined mainly by experience[15,16].
Following is the concrete realization process: (1) In order to manipulate the control gains, a GA coding must be developed, the fuzzy PID controller’s parameters kp, ki, kd, and the quantitative factors ke, kec, which are represented using eight bits, separately coded into {10101110;10101011;10001101;000111110; 11010100;10101010;1101011}.

Transmission electron microscopy and X-Ray diffraction analysis were carried out to investigate the effects of V/III ratio and nanowire diameter on structural properties and crystallinity changes.
This is because the lack of nanowire due to partly broken and lying on the substrate caused by factors described above.
The resulting crystal shape is accordance with the properties of hexagonal shape in magnified TEM results.
Growth and optical properties of nanometer-scale GaAs and InAs whiskers.
The Effect of V/III ratio and catalyst particle size on the crystal structure and optical properties of InP NWs.

Among them, polymer materials, with their unique properties and advantages, occupy a large proportion in biological materials and are widely used in cardiovascular, bone repair, nerve transmission, skin, organs, controlled release of drugs and other fields As for the polymer biomaterials implanted into human body, the complex and strict requirements must be met in the foot, which requires the polymer materials to meet the following requirements: no toxicity, no teratogenic; Excellent biocompatibility: high chemical stability: suitable physical and mechanical properties; Easy to process and shape; Better yield/price ratio[7-8].
Femtosecond Laser Processing of Polymer Materials The advantages of macromolecular materials in cost, mechanical properties, functional pertinence and technological complexity make it gradually replace some inorganic materials or metals, thus a variety of macromolecular materials based devices have appeared.
Biocompatibility can be simply summarized as material accepted by the body, which is the synthesis of physical, chemical and biological properties of the material itself.
Including material and tissue or blood produced by the long-term exposure to biological reactivity, also including the foreign substances in the body under the influence of the factors of its function, physical and chemical changes.
The surface morphology, surface properties, and electrical properties of the polymer materials are also highly compatible.

Considering a weighting factor and taking integrated natural frequency of the column as an optimization objective, the mass of the column as a constraint, an optimization equation is established.
For finite element analysis, all the materials have the properties: young’s modulus, Poisson’s ratio, and density .the vibration mode shapes associated with the frequencies of the column were obtained from modal analysis.
Currently, information on how the response of a structure is affected by changes of the variables that define its shape plays an important role in structural shape optimization.
Dynamics simulation analysis of column for large-scale NC gear hobbing machines [J], Chinese Journal of Mechanical Engineering, 2013,24(11)1473~1478
Study on method for weak link identification of dynamic stiffness of a machine tool and optimization design[J], Journal of Mechanical Engineering, 49(2013)11~17

Combined with the structural characteristics of solid sections of lower pylon column and taking into account the influence of such complex factors as atmospheric temperature, curing method, cooling water temperature drop, ambient temperature changes, external constraints and concrete creep during construction [3], related calculation parameters were determined according to the actual conditions and the temperature and thermal stresses distribution of mass concrete in solid sections of lower pylon column was simulated by using large finite element analysis software.
The minimum safety factor at all the ages of solid sections of lower pylon column is high (>1.3), but stress concentration occurs easily at the junction of the first layer of concrete and the pylon base concrete and inside the chamfer of the second layer of concrete, so thermal insulation and moisture retention curing should be strengthened at these positions.
Physico-mechanical and thermal parameters of concrete of lower pylon column Position Splitting tensile strength (MPa) Final elastic modulus (GPa) Thermal expansion coefficient (1/℃) Thermal conductivity (kJ/m·d·℃) Specific heat (kJ/kg·℃) Adiabatic temperature rise (℃) 3d 7d 28d 180d Solid sections of lower pylon column 2.00 3.40 4.20 4.50 45.0 8.0×10-6 258.5 1.0 47.9 Fig.2.
Envelope diagram of temperature in concrete Table 3 Maximum temperature and thermal stress of concrete of lower pylon column Position Maximum temperature (℃) Maximum principal tensile stress (MPa) 3d 7d 28d 180d First layer of concrete 70.4 1.28 1.79 2.59 2.54 Second layer of concrete 71.4 1.48 1.40 1.57 1.46 Minimum safety factor / 1.35 1.90 1.62 1.77 Temperature control standards.
Combined with the special subject on concrete quality control for the main bridge of Jiashao Bridge, fresh concrete moisture measuring instrument (W-Checker) was used to monitor the water consumption of concrete mix during the construction of solid sections of lower pylon column to prevent blind adjustment of water consumption based on the working performance of concrete resulting in large deviation from the theoretical design value so as not to affect the tensile strength and ultimate tensile properties of concrete.

In order to protect the lives and property of mine workers, the influence of rocks materials slope induced by coal mining was presented.
Combined with the geological environment conditions of slope, rock structure and human engineering activities, the evolution of the slope can be divided into the following phases: The initial deformation stage.Affected by the fault, the hanging rock on the rock exists under the disk compression, and the foot of a stress concentration, slopes broke in the weak layer (mudstone, the contact zone between layers, etc.) and near the foot of rock, then cracks were formed, and to extended at both ends of each link.
The selected rock (soil) parameters such as physical and mechanical properties are shown in Table 1.
rock（（（（soil）））） Type of rock (soil) E / MPa c / MPa υ γ / Nmm -3 φ / ° Loess Homogeneous degree 1 1 100 100 24 Average 80 33 0.40 2.7×10 -5 Sandstone and mudstone layer Homogeneous degree 3 3 100 100 35 Average 2000 1 0.30 2.5×10 -5 Mudstone Homogeneous degree 2 2 100 100 25 Average 1000 1 0.35 2.3×10 -5 Sandstone Homogeneous degree 3 3 100 100 45 Average 3000 3 0.25 2.5×10 -5 Coal Homogeneous degree 1 1 100 100 28 Average 1000 2 0.27 1.5×10 -5 Limestone Homogeneous degree 4 4 100 100 40 Average 4000 11 0.35 2.6×10 -5 Fault belt Homogeneous degree 1 1 100 100 25 Average 10 1 0.40 1.8×10 -6 Note: ratio of compressive and tension is 1/10; Residual threshold coefficient 0.1; Maximum strain coefficient is 1.5; The maximum compressive strain coefficient is 200; poisson ratio coefficient after the destruction of loess is 1.0; rock destruction poisson ratio coefficient is 1.2; and reduction factor
References [1] Reng Guangming, Nie Dexin, Liu Gao, Studies on Deformation and Failure Properties of Anti-Dip Rockmass Slope , Chinese Journal of Rock Mechanics and Engineering, 2003 22(suppl 2):2707-2710

The advent of nanostructured materials and the need to design microelectronic and micromechanical devices with length scales of nanometers require not only a profound understanding, but also a reliable prediction of mechanical properties of such structures.
From the comparison of the model results with experimental data we can conclude on the importance of the different influence factors on creep in thin films. 2 Discrete dislocation model A model of diffusional creep in a thin film geometry with a single grain boundary is set up here.
In the present work we have restricted ourselves to the case where the elastic properties of film and substrate are identical, which is a very good approximation for a copper film on a silicon substrate.
Nix, Mechanical properties of thin films, Metallurgical Transactions A 20 (1989) 2217-2245
These values mimic material properties of copper.