Applied Mechanics and Materials Vols. 34-35

Abstract: This paper proposes a representation and measurement method for compressed air power widely used by various industries in the industrial. It proposes an accurate and standardized way to represent and measure the power energy in unit time of the flow compressed air, then establishes the evaluation system in energy distribution, loss and use in pneumatic system, which can clear the energy loss in pneumatic system and its components. Pneumatic power transducer designed in accordance with pneumatic power, it has advanced functions and higher precision, which can promote the energy efficiency greatly in pneumatic system.

Abstract: The non-linear diffusion techniques were proposed for overcome the linear diffusion defaults. The linear diffusion was a homogeneous diffusivity with a constant conductivity. In this diffusion process, the noise and the edges were smoothed in the image. In order to prevent the edge from being smoothed during the denoising, the nonlinear diffusion was proposed by Pereona and Malik. In this method, noise was smoothed Simultaneously with the edges blurred. In diffusion processes, the conductivity is dependent on the image local information. We analyzed the ineffectiveness of isotropic and extended the work into the tensor-based anisotropic diffusion. It would be desirable to rotate the flux towards the orientation of interesting features. We compare the difference of isotroic linear and non-linear anisotropic diffusivity, and considere how to design non-linear anisotropic conductivity based on the different requires of the image filtering.

Abstract: For degassion of high-viscosity and high-density drilling fluid used in ultra-high pressure oil and gas zones, a two-stage vertical separation system was established. In this system, gravity separator was used as the first separator and the second separator was centrifugal separator. Using orthogonal experiment method, we simulated flow field in this system by CFD software and analyzed the effect of operate variable and structural variable on system degassion efficiency. In accordance with the characteristics of flow fields, the performance optimization scheme was presented.

Abstract: Based on loaded tooth contact analysis of spiral bevel gears, the thermal analysis model and finite element model of spiral bevel gears were established by making use of tribological theory and thermal transferring theory. The distribution on transient temperature field of spiral bevel gears under loss of lubrication was found via finite element methods. The results are as follows: the sliding speed and normal load had obvious influence on friction heat. Transient temperature peak value of the gear tooth was obtained in midpoint position of the tooth contact path. The temperature gradient increases with the increase of meshing times of gear tooth, the transient temperature of the gear tooth surface had increased 32°C in one minute. However, the transient temperature of the tooth surface had increased 232°C in three minutes.

Abstract: The wide application of Location-Based Service (LBS) makes location privacy and trajectory privacy receive much attention in recent years. The basic idea of current privacy preserving methods in LBS is cutting the relationship of user’s consecutive locations. This paper propose LOCMIX, a trajectory privacy protecting method which is based on neighbor node’s forwarding query in a P2P LBS system. Choose the user who have sufficient power to forward queries to LBS as the forwarding node of user u. The forwarding node must be as close to user u as possible. Then the k-Anonymity Spatial Region (k-ASR) was constructed with the forwarding node and the k-1 users whose Hilbert value is less than (or more than) the forwarding node. The experiments show that LOCMIX has good load balancing property and protect trajectory privacy effectively against the “center-of-k-ASR” attack and the correlation attack.

Abstract: Experiments were conducted to investigate the saturated flow boiling heat transfer characteristics in single micro tube using environmentally acceptable refrigerant mixtures R32 and R134a. Local heat transfer coefficient was measured and boiling heat transfer mechanisms were discussed for a range of heat flux (3-65 kW/m2) , mass flux (860-4816 kg/m2•s) and quality (0-0.9). These characteristics indicated that the local heat transfer coefficient was greatly dependent of heat flux and independent of mass flux and quality in the nucleate boiling regime, which was oppsite to that in forced convection regime, and deterioration of boiling heat transfer occurred in the local dry-out regime. In addition, a correlation for nucleate dominant boiling in micro tube was developed ,which included the effects of heat flux and fluid property and showed some success with the data of this study within a 20% random error band.

Abstract: To get an accurate prediction and analysis results of static and dynamic characteristics of the whole machine tool, finite element model should consider adding characteristic parameters to each pair of the combined interfaces when being built. Taking XDK650X engraving and milling machine as an example, integrating the combined interface parameters into the whole machine tool model with the help of finite element method, the dynamic model contained combined interface characteristics of the whole machine tool was built, and investigation on static and dynamic characteristic were carried out. Then, the relative stiffness between the tool and the platform was analyzed by using harmonic respond analyzing method. It was concluded that XDK650X engraving and milling machine has bigger static stiffness in three directions compared with other similar machines, but has comparatively smaller static stiffness in X direction, a bigger relative vibration amount between the tool and the platform in Y direction. Therefore preponderant natural frequency should be avoided in usage, the static stiffness in X direction and the dynamic stiffness in Y direction need for enhancement in structural optimization.

Abstract: Nano-coatings were prepared by sol-gel process using titanium butoxide and cerium salt as precurors. The substrates were coated by dip-draw method. The structure of nano-coating was characterized by X-ray diffraction (XRD). The degradation activities of nano-coatings were evaluated by testing their efficiency in removing acetone and decane. Results show that the conversion rate of decane and acetone by TiO2 nano coating doped 1.0 wt % Ce was much higher than that of common unmodified TiO2 nano coating.

Abstract: The intensity distribution of a UV linear light source and a UV linear light with a parabolic cylinder reflector on work piece surface were simulated using OpenGL program based on VC++6.0. Physical models were established and relevant fundamental assumptions were given. The results of the simulation fitted the real situation quite well. It is feasible to adjust the parameters of UV-curing radiation system using the results of computer simulation.

Abstract: Non-Structural road driving test is a key part of fatigue and durability tests for vehicles such as the construction machines and ATVs. Combining a theoretic road-tyre dynamic model with some real vehicle design parameters, the responses of the wheel axle under different non-structural road conditions were estimated conveniently. The responses can be taken as inputs for a virtual test-rig simulation, and the responses of every part on the test object are obtained separately. Fatigue life is predicted under the finite element circumstance, and the reliability and durability are concluded. Comparing with the real road-driving test, the virtual fatigue test method above can significantly reduce the test period. This method is used to predict the fatigue life of the rear axle-housing in construction machines, the accuracy of the method is verified by a corresponding real bench test.