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The development of drag and lift balance aimed to modify and creating a measuring instrument that may be used in the field of aerodynamics or in testing aerodynamic properties.
The Mechanical Engineering Laboratory of the Muhammadiyah University of Surakarta already has a wind tunnel with the Low Turbulence Subsonic type, but for about 20 years the tool has not been functioning.
Drag Coefficient of Airfoil Based on Figure 2 and Figure 3, it can be seen that the values of CL (lift coefficient) and CD (drag coefficient) are nearly identical and are not affected by the aspect ratio and velocity, although there are discrepancies at an aspect ratio of 1.6, which could be attributed to testing factors.
Typically set at 15 degrees, the angle of attack can significantly vary based on fluid properties, foil characteristics, and aircraft type.
The motivation from head of laboratory on mechanical engineering department is also acknowledged.

It has been reported many times that quaternary AlCrSiN coatings promote a higher level of properties than typical TiAlN or CrAlN coatings [1,2,3].
Every type of coated cemented carbide turning insert was tested three times in order to exclude the impact of other factors involved in the process.
Cavaleiro, “High-temperature tribological properties of CrAlN, CrAlSiN and AlCrSiN coatings,” Surf.
Lee, “Effect of cathode arc current and bias voltage on the mechanical properties of CrAlSiN thin films,” Surf.
Mitterer, “Influence of Al and Si content on structure and mechanical properties of arc evaporated Al–Cr–Si–N thin films,” Thin Solid Films, vol. 534, pp. 403–409, May 2013

Introduction Abrasive water jet is a new technology which rapid rise in the 1880s, compared with the traditional processing technology, as a kind of cold processing[1], It has many advantages as follows: first, it does not change material basic mechanical, physical and chemical properties in the machining process ;second,it hasn’t processing residual stress;thirdly, the parts that has special requirements such as local cannot have the change of heat, the workpiece surface can't have processing knife grain ,can process by high pressure abrasive water jet.
At present general methods of blade polishing are: six coordinate abrasive belt grinding, peening[3] and vibration strengthening, etc.but these methods have some defects as follows:in one hand, when we polish workpiece using sand machine,it is easy to cause the workpiece heat distortion[4] beacause of friction between sand grain and workpiece getting hot; in the other hand,Three dimensional vibration strengthening and polishing can only for some small blade; Thirdly, when using six coordinates abrasive belt cuts blade[5], blade root and convex platform cannot be polished, and should often change sand belt, which seriously affects the processing efficiency and increases the processing cost[6].
Figure 3 200 Mpa, 90 °, 1000 mm/min pure water jet erosion surface morphology The experimental research shows that the impact action makes the material fracture and flake to remove when abrasive water jet angle of incidence is vertical 90 °. with the same process parameters of pure water jet under,when abrasive flow is 180 g/min, abrasive water jet removal is 99.3 mg/s, the removal rate of abrasive water jet is much higher than pure water jet. but the material surface will appear erosion pit formed by a lot of abrasive the impact action, which seriously affected the material surface quality.
Figure 4 120 Mpa, 30 °, 2000 mm/min abrasive water jet Conclusion (1) Based on the experimental research, the pressure of water jet is the main parameters which affects the removal rate.
(2) The incident angle is the main parameters which affects material processing surface morphology.

Material Properties All materials were considered as isotropic, homogenous, and linearly elastic (Table 1). 
Table 1 Mechanical properties of bone and implant materials [5-11] Component Material E (GPa) n Bridge framework Chrome/Cobalt 218 0.33 Implant Titanium 110 0.35 Bone Cortical bone 13.7 0.3 Spongy bone 1.5 0.3 4.
Element quality check was performed to avoid skewed elements that could affect the results.
The results of this study showed that biomimetics is one of the better solutions for prosthodontics success in dentistry: the optimization and reliability of dental cares have to take into account the mechanical properties of natural tissues and respect the physiology of the patient.
Wolf, Nonunion of the mandible: An analysis of contributing factors.

The openness of the network security problem The openness of the Internet and other factors led to the computer system under network environment many security problems.
(2) the use of security tools affected by human factors.
A security tool can achieve the desired effect, to a large extent depends on the user, including system administrators and ordinary users, improper setting can produce anxiety All factors.
(as shown in figure 4.1) rename administrator account "properties" dialog box, in this input new name of the administrator, as far as possible put it for ordinary users, and then built a more than ten super complex passwords, and enable the audit of the account, so even if the hacker to code and hard to kill.
Beijing: mechanical industry press, 2008.1:36 to 38 [8] photocopying.

Thus nano-TiO2 in the hot rolling lubricant oil can also affect the wall energy, mechanical slip and thermal slip between the oil film and work roll under the contact area, and finally influence global lubrication.
Spikes, The effect of emulsifier concentration on the lubricating properties of oil-in-water emulsions, Tribol.
Yoshida, Influence of lubricant factors on coefficient of friction and clarification of lubrication mechanism in hot rolling, Tetsu To Hagane-J.
Wen, The tribological properties of oils added with diamond nano-particles, Tribol.
Xu, Effect of UV irradiation on mechanical properties and structure of poly(1,3,4-oxadiazole) fibers, Polym.

Research of impact of stray current from urban rail transit system on buried gas pipeline Zhiguang CHEN Chaokui QIN Yangjun ZHANG Jixu TANG College of Mechanical Engineering, Tongji University, Shanghai 200092, China Keywords: stray current, rail transit, buried gas pipeline, pipe-to-soil potential, current within pipeline.
Dynamic properties of SC from transit system lead to the necessity of using appropriate measurement technique, such as continuous chart recorder or digital data logger.
Fig.1 The pipeline-soil potentials vs. time Fig.2 The current within pipe vs. time Fourier Transformation and Frequency Analysis The field testing of pipe-to-soil potential could be affected by various factors, e.g. the power supply system of rail transit, power grid, road vibration, etc.
The changes of pipe-to-soil potential were also affected by external coatings of the underground pipelines, soil resistivity and other parameters of the earth.

Such joints may appear an impression of insecurity,and have problem of the mechanical properties.It is difficult to reach the effect of the assumed rigid,in that case,it undermines the security of the node degree.
It can be seen that the structure type of nodes is complicated, the outline of nodes increased, affecting construction appearance.The bars in both directions were connected through a steel bar,that coursed the bearing capacity of the node region a big challenge, brought insecurity.
Also it led the disconnect the steel components in the node design difficult to achieve the effect of the assumed rigid, more hinged elements.This type of structure has a large deformation and the node jurisdictions, particularly the armor plate which played an important role of connection,contacted with air a large area, creating difficulties for anti-corrosion structure.Considering the above factors, the proposal of the node are no longer feasible.

Introduction In connection with to the intensive development of different sectors of economy as microelectronics, robotics, micro mechanics, precision mechanical engineering, biology, medicine and others; the necessity of electromechanical device for carrying all manner of objects is growing, including minuscule objects with micron and sub-micron accuracy, and also the accomplishment of any operation (e.g., micro-assembly) [1,2].
As a rule, it is possible in the study of mathematical models of actuators, when the dynamic properties v(t) and a(t) are solutions of the differential equations.
This error can be divided into: accumulated - proportional difference over the full working stroke of the valid motion from the given one (it's defined by discrepancy between the carving valid step and the gotten one, by the location deviation of the surfaces throughout the full length of the component); cyclical - error made by the form and position deviations within one revolution limits of every component of the mechanism (e.g., roundness); probability - error determinate by the surface roughness and other non-systemic factors.
To implement the measures, it's the necessary a special stand that allows carry out the observations of the motions of the output link with sufficient accuracy, because it affects the quality of the correction, and, as a consequence, the kinematic accuracy of motion of the lead nut.
For example, in the treatment with the CNC machine of precise curved surfaces the unsmooth motion of the robotic arm leads to the unevenness of the serve, which affects the quality of treatment.

Based on the experimental and calculation results between the reinforcing particles content and thermal physical parameters, low pressure die casting of wheels was taken as an example to study the casting property of the 7075 alloy and TiB2/7075 composites.
Numerical simulation has calculated the temperature field and stress field in mould filling and solidification process, defects and microstructure, which affected by the of gating system design and processing parameters, such as casting temperature, casting pressure, mold temperature.
The effect of grain refinement on the viscosity of composite depends on many factors of reinforced particle, such as itssize, shape, amount and even its agglomeration in the matrix[13].
Lu, Processing, microstructure and tensile properties of nano-sized Al2O3 particle reinforced aluminum matrix composites, J.
TorabiParizi, Comparison of microstructure and mechanical properties of A356 aluminum alloy/Al2O3 composites fabricated by stir and compo-casting processes, J.