Applied Mechanics and Materials Vols. 121-126

Abstract: Traditional data mining often focuses on the research of models and methods without considering of specific requirements in the field. This paper proposes a data mining framework in traffic field—Traffic Domain Data-Mining Framework (TDDMF) which is a domain-driven data mining framework based on ontology. The ontology model for traffic domain data based on TDDMF is also built in the paper. A prototype system is developed to prove the availability and effectiveness of TDDMF.

Abstract: Cr-α-Al₂O₃ composite coatings were prepared by direct current deposition experiments from Cr(Ⅲ) plating bath and the thickness of composite coatings could be up to 14 μm. The obtained Cr-α-Al₂O₃ coatings and Cr coatings were characterized by means of EDS, SEM and microhardness measurement. Results revealed that Cr-α-Al₂O₃ coatings exhibit fine-grained structure with uniform surface and the highest microhardness values(692 HV) when the α-Al₂O₃ content of coatings was 15g/L, although some pores and defects are still present in the coatings. Analysis of Tafel curves indicated that the presence of α-Al₂O₃ in the Cr coatings show better features in the corrosion resistance both in H₂SO₄ and NaOH solution than those prepared from the bath without α-Al₂O₃.

Abstract: Al-Ni Alloys were obtained from NiCl2-AlCl3-1-ethyl-3-methylimidazolium bromide ([EMIM]Br) ionic liquid at room temperature. The analysis of Al-Ni alloys that co-deposited at different potentials for 2h were performed using Scanning Electron Microscopy (SEM) and X-ray diffraction analysis (XRD). It appears that Ni has been rapidly solidified in the alloys and homogeneous Al-Ni alloys can be obtained at room temperature. As increasing the overpotential, the amount of Ni in the alloys was decreased whereas the amount of Al was increased. The chloride pitting potentials of alloys with the molar ratio of NiCl2/AlCl3/[EMIM]Br 0.03:2:1 was approximately 0.3 V more than pure Al.

Abstract: This paper presents a novel technique for coloring stainless steel utilizing a fiber laser. This study develops a processing technology that uses a fiber laser as a laser marking tool, and varies processing parameters such as pre-surface-processing conditions, stainless steel type, line distance, laser power, engraving speed, and laser pulse frequencies to achieve different results. This study investigates the results of the stainless workpiece coloring using optical microscope (OM). This study shows that polished stainless steel 316 exhibits the best engraving effect. With this material, the line distance, laser power, engraving speed, and pulse frequency of the laser change the oxidation thickness. The color of the processed workpiece also changes as the oxidation thickness changes due to the interference caused by the different thicknesses of the oxidation layers. Results prove that fiber laser processing of stainless steel is a promising and efficient technique for coloring stainless steel.

Abstract: The compressive behaviors of AZ31-Zr foams using Ca particles as thickening agent and CaCO3 powder as foaming agent were investigated in this study. The porosity was about 48.7%~72.9%, pore size was between 0.43~0.97 mm, and homogenous pore structures were obtained. Mechanical properties of AZ31 Mg alloy foams were investigated by means of UTM. The cellular AZ31 Mg foams possess superior comprehensive mechanical properties. The energy absorption characteristics and the effects of compression behavior on the energy absorption properties for the cellular AZ31 Mg foams have been investigated and discussed. The results show that with the addition of Zr, the Mg alloy foam has the highest energy absorption value of 16.26 MJ/m3 and the hardness value of 81.8 HV, which is much higher than that of the foams fabricated without Zr.

Abstract: Based on TEOS system and sol-gel process, together with catalysts, the microstructure of SiO2 particles in the sol is exactly controlled. The films are characterized by ellipsometer and SEM respectively. The experimental results show that adjusting catalytic time can effectively effect the uniformly porous structures of SiO2 thin film on the glass substrate.

Abstract: The design or assessment method to identify the safety of all the materials or components in accordance with the specific service environment is called design or assessment method for applicability. The assessment method for material applicability is set forth in Standard API 579.The most important step in applicability design is to simulate the practical conditions on the site as close as possible. However, limited by material, manufacturing level and cost, etc., it is hard to simulate the real environment in the laboratory test. Therefore, the testing condition and method should be designed scientifically to allow the testing result to close to the practical condition as much as possible. At present, as for the design of the gas component, the content of each component during the test is designed based on the principle of partial pressure equalization of corrosive component according to the actual pressure and the gas components on the site. But the author assumes that the principle of dissolved amount equalization for the corrosive components in the solution shall be adhered to in the process of applicability assessment. The paper mainly introduces the method to calculate the partial pressure of each component, the model to calculate the solubility of the corrosive components in the solution, and finally gives the example of calculation and points out the problem existing in the partial pressure equalization principle.

Abstract: This paper presented a novel control scheme for electro-hydraulically driven parallel robot, in order to improve control performance by eliminating the effect of system coupling in controller. The mathematical model of the electro-hydraulic parallel robot is formulated, including mechanical system and electro-hydraulic system, using Kane method and hydromechanics principle. The decoupled space is exploited for electro-hydraulic parallel robot by using singular value decomposition (SVD) approach. In the decoupled space, a simple but effective controller is developed with only actuator position as its feedback. Theoretical analysis and numerical simulation results show that the proposed control greatly overcomes the drawbacks of dynamic coupling in the workspace of parallel robot and exhibits excellent control performance, especially tracking performance.

Abstract: In this paper, the effects of Bi2O3 addition on the electrical and physical properties of 0.98(Na0.5K0.5)NbO3-0.02(Na0.5Bi0.5)TiO3 were investigated. The 0.98(Na0.5K0.5)NbO3 -0.02(Na0.5Bi0.5)TiO3 [0.98NKN-0.02NBT] ceramics with the addition of 0~0.5 wt% Bi2O3 have been prepared following the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all of the (Na0.5Bi0.5)TiO3 diffuse into the lattice of (Na0.5K0.5)NbO3 to form a solid solution, in which a orthorhombic phase with a perovskite structure was found. For 0.98NKN-0.02NBT ceramics by doping 0.1 wt% Bi2O3, the poled dielectric constant (K33T) and the electromechanical coupling coefficients of the planar mode kp reach 684 and 0.38, respectively, after sintering at 1100 °C for 3 h. Our results show that 0.98NKN-0.02NBT with the addition of 0.1 wt% Bi2O3 is a good lead-free piezoelectric ceramic.

Abstract: Effect of black plate on growth action and corrosion resistance of Sn-Fe alloy film was investigated by means of metallurgical microscope, scanning electron microscopy (SEM), salt spray corrosion test and electrochemistry methods. The results show that the different modes of annealing and rolling have a remarkably effects on the surface morphology and grain size of Sn-Fe alloys. Crystalline grain of Sn-Fe alloy film for T4-CA or T2.5-BA is relatively continues, homogeneous and denser, but that for DR materials exists obviously surface inhomogeneity sizes and even void space of interweave. Rust spot easily generate on discontinuous alloy films or void space of interweave growth and gradually cover on the surface of Sn-Fe alloy films without corrosion damage. Corrosion resistance of BA materials is better than that of CA materials. Under the same annealing mode, corrosion resistance of DR materials is worse.