Applied Mechanics and Materials Vols. 55-57

Abstract: Thermo-sensitive copper/paraffin nanocomposites were prepared by high energy ball milling. Fourier transform infrared spectrometer (FTIR), x-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to analyze the composition, phase and microstructure of the composites. Furthermore, their thermal sensitivity was investigated. Results reveal that the phase of composites is mainly composed of copper, paraffin and a small amount of cuprous oxide copper. Nanoparticles homogeneously covered by paraffin form the similar core-shell structure. The mass ratio of copper to paraffin has an obvious influence on the thermal sensitivity.

Abstract: The modification of Nano Pt and carbon black compound coating on the fuel cell’s graphite electrode by the method of vacuum ion plating and ethanol catalytic combustion. The microstructures and the electro catalysis properties of the electrode surface before and after the modification were analyzed and tested with the methods of scanning electron microscope(SEM), transmission electron microscope(TEM), electrochemical workstation and so on. The effects of nano Pt and carbon black on the electrode’s electro catalysis properties were investigated. The Study results have shown that carrying on electrochemical properties test to the graphite electrode which has been treated with nano Pt and carbon black compound surface modification, there will be three oxidation peaks in its cyclic voltammograms and the background current will be higher. Compared with the nano Pt surface modification, the electrode which has been treated with nano Pt and carbon black compound surface modification has better ethanol electro catalysis properties. The high specific surface area acquired from the nano carbon black surface modification and the synergic action of the catalytic material Pt can improve the ethanol electro catalysis properties of the electrode effectively.

Abstract: The case was carried out to study the variance of fiber feature, chemical composition and pulping property between heartwood and sapwood of Cedrus deodara (Roxb.)G. Don. As results showed, the mean fiber length in heartwood and sapwood of cedar were 1842 and 2552 µm separately, with the length-to- width ratio of 77.46 vs 79.41, and the wall-to-lumen ratio of 0.36 vs 0.38, respectively. The heartwood of cedar differed from sapwood in contents of chemical compositions, with holocellulose of 70.00% vs 75.87%, α- cellulose of 40.75% vs 42.75% and lignin of 26.64% vs 25.00%, respectively. Both the heartwood and sapwood of cedar were excellent pulping material. By investigating pulp yield and Kappa number, it was proven that the caustic soda dosage and the duration of reaction temperature were major factors influencing KP pulping properties of cedar sapwood. Under the same technical conditions of pulping, the pulp of the cedar sapwood was lower in Kappa number and higher in yield and in viscosity compared with those of heartwood. The tensile index, tear index and burst index of paper made by sapwood were higher than those made by heartwood. The sapwood of cedar showed overall better pulping aptitude in comparison with heartwood.

Abstract: Using an alternative pulse current source and in silicate solution electrolyte，a uniform coating on the surface of AZ9lD alloy was fabricated by micro-arc oxidation(MAO) with current density of 40mA/cm2. Friction wear testing machine was used to study the wear behavior under corrosive environment of the film and scanning electron microscopy(SEM)were used to study microstructures of film and worn surface．The result shows that the corrosion resistance of micro-arc oxidation film is large better than that of magnesium alloy. The corrosive solution great weaken the abrasion resistance of the coating. As the influence of the corrosive solution, the wearing mechanism is varying with the loading. Abrasive wear is the main mechanism when the loading is small, if the loading is large enough, the binding force will be destroyed and the coating will peel off from magnesium alloy.

Abstract: In this paper, a dual-resource constrained job shop scheduling problem was studied by designing a hybrid genetic algorithm based on Genetic Algorithm (GA) and Simulated Annealing (SA). GA is used to search for a group of better solutions to the problem of minimizing production cost and then SA is applied to searching them for the best one. The combination of GA and SA utilizes the advantages of the two algorithms and overcomes their disadvantages. The operation-based encoding and an active schedule decoding method were employed. This hybrid genetic algorithm reasonably assigns the resources of machines and workers to jobs and achieves optimum on some performance. The results of numerical simulations, which are compared with those of other well-known algorithms, show better performance of the proposed algorithm.

Abstract: Auto panel stamping is a complicated plastic deformation process with geometry nonlinear, material nonlinearity and numerous process parameters. The stamping process of a typical auto panel wheel wrap was studied by artificial intelligent optimization and physical experiment. The prediction model of object function was established using artificial neural network. In object function, blank-holder force, drawbead height and fillet radius were selected as the optimized variables and prevention of rupture was considered as the optimization objective. Process parameters optimization was performed with genetic algorithm. The optimized process parameters were used to guide die design and testing, and the result of wheel wrap stamping showed that the forming quality was obviously improved. So the process optimization based on artificial neural network and genetic algorithm is feasible and efficient for auto panel stamping.

Abstract: At present, the fifteen percent of auxiliary power is consumed in pulverized coal in power plant, and most of which is lost in the form of heat. So the study how to make mill work efficiently arouses the interest of many researchers. A method based on data mining is presented in this study to improve the operarion charateristic of ball mill.

Abstract: The paper presented the improved “one to many” classification algorithm in the basis of analyzing the shortcoming of the two traditional multi-classification algorithm, and established multi-fault classifier based on SVM to class the turbine typical faults. The results shows that the classifier may get satisfied effect.

Abstract: Ship oil spill is one of the most serious marine pollutions. By assessing the risk of oil spill’s diffuseness, revealing the complex rules of its occurrence and taking appropriate preventive and emergency measures, we can minimize the pollution. With Yangshan’s waters in Shanghai as the background, this paper, using hierarchic analysis, gives a model of risk assessment on the oil spill’s diffuseness in Yangshan and a risk assessment on the oil spill’s diffuseness on the real ship, providing a scientific basis to effectively avoid pollution caused by oil spill diffuseness.

Abstract: In order to measure ability of maintenance system to accomplish maintenance tasks, this paper studied maintain performance analysis method pointing to the industrial maintenance system. Based on defining the maintenance efficiency, this paper put forward three maintenance efficiency indexes: rate of maintenance tasks completion, rate of fault clearing and rate of maintenance system losing. This paper established a system maintenance performance analysis model using Markov stochastic process theory. With anglicizing the example, this paper draws three principles: moderate maintenance, availability, and credibility, then lays a foundation of exploring the way to improve maintenance system effectiveness.