Applied Mechanics and Materials Vols. 48-49

Abstract: Strain and strain rate are two important parameters evaluating plastic deformation of workpiece in cutting process. Finite element simulation is implemented to estimate plastic deformation of wokrpiece in this paper. Flow net function in simulation is used to capture deformation state of grids on workpiece, and the deformation result is compared with that observed by Stevenson and Oxley in cutting test. Point tracking function in simulation is utilized to calculate strain and strain rate distribution along flow lines, and the results are also compared with that calculated by streamline model.

Abstract: To improve the texture image retrieval rate of contourlet texture image retrieval system, a contourlet-1.3 transform based texture image retrieval system was proposed. In the system, the contourlet transform was contourlet-1.3, a new version of the original contourlet, sub-bands absolute mean energy and kurtosis in each contourlet-1.3 sub-band were cascaded to form feature vectors, and the similarity metric was Canberra distance. Experimental results on 109 brodatz texture images show that using the features cascaded by absolute mean energy and kurtosis can lead to a higher retrieval rate than the combination of standard deviation and absolute mean energy which is most commonly used today under same dimension of feature vectors. Contourlet-1.3 transform based image retrieval system is superior to those of the original contourlet, non-subsampled contourlet and contourlet-2.3 systems under same system structure with same dimension of feature vectors, retrieval time and memory needed.

Abstract: This paper introduces a computer control network system which can control sintering process of four PTFE molding furnaces accurately. System in-out signals such as sintering temperature, on-off signals of dial motor and aeration motor were connected to Lonworks via net nodes, and network variables were used to construct a configuration and interlinkage between the net nodes. We chose a combined-control strategy in which On-off control or Fuzzy-control or Fuzzy-PID control strategy were selected automatically, so the needs to sintering time, cooling speed, steady-state precision etc were accurately achieved.

Abstract: In this paper, a control strategy for operation of rotor side converter (RSC) of Doubly Fed Induction Generators (DFIG) is developed by injecting reactive power into the grid in order to support the grid voltage during and after grid fault events. The novel nonlinear control method is based on differential geometry theory, and exact feedback linearization is applied for control system design of DFIG. Then the optimal control for the linearized system is obtained through introducing the linear quadratic regulator (LQR) design method. Simulation results on a single machine infinite bus power system show that the proposed nonlinear control method can inject reactive power to fault grid rapidly, reduce the oscillation of active power and improve the transient stability of power system.

Abstract: A co-sol-gel method was used to prepare SiO2-doped TiO2. The amount of ethyl silicate added into the precursor, calcination temperature and time, adsorption equilibrium, and photocatalytic activity of the material were investigated as the factor of degradation efficiency. With the optimum composition of the precursor, the prepared gel calcinated at 500 oC for 3 h showed the highest photocatalytic activity. After 30 min stirring to reach adsorption equilibrium, adsorption contributed less than 2% to the total decoloration of methyl orange on the SiO2-doped TiO2 material. Photocatalytic methyl orange degradation continued with increasing irradiation time. Methyl orange degradation rates after 30 min and 100 min were 31.1% and 96.9%, respectively.

Abstract: Monitoring of metal cutting tool wear for turning is a very important economical consideration in automated manufacturing. In the process of turning, the vibration signals of cutting tool become more and more irregular with the increase of tool wear. The degree of tool wear can indirectly be determined according to the change of vibration signals of cutting tool. In order to quantitatively describe this change, the wavelet and fractal theory were introduced into the cutting tool wear monitoring area. To eliminate the effect of noise on fractal dimension, the wavelet denoising method was used to reduce the noise of original signals. Then, the fractal dimensions were got from the denoised signals, including box dimension, information dimension, and correlation dimension. The relationship between these fractal dimensions and tool wear was studied. Use these fractal dimensions as the status indicator of tool wear condition. The experiments result demonstrates that wavelet denoise method can efficiently eliminate the effect of noise, and the change of fractal dimensions can represent the condition of tool wear.

Abstract: In this paper, the method of data compression in ultrasonic automatic inspection using integral wavelet transform is proposed. The compression method presented is performed through signal decomposition, thresholding of wavelet transform coefficients, signal reconstruction, evaluating and optimizing algorithm performance by parameters index . The experiments show that the method has the advantages of low computation complexity， fast compression rate， high compression ratio and small reconstruction difference when it is applied to A-Wave data compression.

Abstract: By introducing a degree dominance relation to dominance interval intuitionistic fuzzy decision systems, we establish a degree dominance interval rough set model (RSM), which is mainly based on replacing the indiscernibility relation in classical rough set theory with the degree dominance interval relation. To simplify knowledge representation and extract some nontrivial simpler degree dominance interval intuitionistic fuzzy decision rules, we propose two attribute reductions of the degree dominance interval intuitionistic fuzzy decision systems that eliminate the redundant condition attributes that are not essential from the viewpoint of degree dominance interval intuitionistic fuzzy decision rules.

Abstract: In this work, the mixing characteristic of ternary diameter particle system in a rectangular spouted bed was carried out three-dimensional discrete element method (DEM). In particular, the standard k- two-equation model and the Beer & Johnson equation were adopted to investigate the influence of turbulence and rolling friction, and Ashton mixing index was adopted to evaluate the dynamic mixing process of the ternary diameter particle systems. The particle velocity profiles, the gas-solid flow patterns, the particles distribution and the effect of gas velocity on mixing are discussed.

Abstract: This theme focuses on representing and reasoning high-level semantic based on concepts and their space relations. As to multimedia data, such as image and video, acquiring, representing and retrieving high-level semantic information has been a confused problem for a long time. Without the support of knowledge database, it is an impossible mission to carry out the simple synonymous retrieval, let alone retrieving the abstract semantic. This paper proposes some algorithms to translate restored concepts and their relations into a Concept Semantic Network, which is visualized by SVG finally. The paper also introduces the method of recording concepts distribution by description logic, which services users with concepts and distribution retrieval.