Applied Mechanics and Materials Vols. 278-280

Abstract: To reduce the noise and vibration of mobile wastewater treatment plant, this paper presents testing and analysis of 50 measuring points in the working state of mobile wastewater treatment plant based on TST test analysis system. The structure’s natural frequency, damping and modal vibration modes are extracted within the frequency band of 0-1000HZ. By comparing the operating modal and the finite element modal, it is believed that the operating modal can accurately recognize modal parameters of the container.

Abstract: In order to improve braking stability and energy recovery ability of electric buses, a new-type electronic-controlled pneumatic regenerative braking system for electric buses was designed. The regenerative braking system controls pneumatic braking force of front and rear wheels by high-speed solenoid valves, which could coordinate mechanical and regenerative braking force effectively. A simulation model of electric bus braking process was established, as well as regenerative braking control strategy. Simulink and AMESim joint simulation analysis of braking process of electric bus was run. The results show that energy recovery of the new-type regenerative braking system is effective and braking control strategy is reasonable.

Abstract: The variable-speed electrohydraulic drive, which can achieve similar energy efficiency as volume drive system, has some good features. But the slow response and poor low-speed performance limit the development of the variable-speed electrohydraulic drive. The energy regulation based variable-speed electrohydraulic drive is a good solution to solve these problems by adding an energy regulation device and a throttling valve into the system. The sine simulations of energy regulation based electrohydraulic variable-speed drive are carried out. The simulation results have showed that the energy regulation system can not only achieve the goal of a good response, but also keep a good energy-saving performance.

Abstract: Based on BP neural network relevant theories, using the fuel consumption, the load and the diesel blended rate as input parameters and measured CO, HC, NOx and soot emission data from bench tests of 180FA diesel engine under various operating conditions as training samples, a double-hidden layer BP neural network model for emission performance in a diesel engine fuelled with bio-diesel was established. The results show that the prediction results of CO, HC, NOx and soot emissions have a good agreement with their experimental ones, and correlation coefficients (R) are very high. It is further shown that the predicted values of HC and CO emissions increase as fuel consumption rate increase, and the predicted values of NOx and soot emissions decrease with the increase of fuel consumption rate.

Abstract: The microwave dielectric properties of (Ca0.2Sr0.8)3Ti2O7 ceramic system have been investigated with various pressure conditions. The compounds were prepared by the conventional solid-state route with various pressure conditions from 60 to 80 Kg/cm2 and sintered at 1450oC for 4 h. The structure and microstructure were analyzed using X-ray diffraction and scanning electron microscopy techniques. The (Ca0.2Sr0.8)3Ti2O7 had excellent dielectric properties: Q×f ~ 50,000 (GHz) and εr ~ 63.2 for the sample at 70 Kg/cm2.

Abstract: During vacuum counter-pressure casting, the vacuumization is an important stage for thin-wall and complicated aluminum alloy castings. Through testing and an analyzing numbers of pinhole and pinhole grade of aluminum alloy samples under different vacuum degree, the effect of vacuum degree on pinhole of vacuum counter- pressure casting molten aluminum alloy is studied. The results indicate vacuum degree has greater effect on pinhole of molten aluminum alloy in vacuumizing process. The smaller vacuum degree is, the more numbers of pinhole of the samples are, and the higher pinhole grade of the samples is. Therefore, when vacuum degree is small, pinhole of molten aluminum alloy appears easily. So the vacuum degree doesn’t choose too small, but for thin-wall and complicated aluminum alloy castings, the vacuum degree doesn’t choose too big either. Appropriate vacuum degree is from 20 KPa to 40 KPa.

Abstract: This paper presents a analytical method to calculate the minimum clamping force to prevent slippage between the workpiece and spherical-tipped fixture elements during milling process. After the contact deformation between the workpiece and spherical-tipped fixture element is determined, the relationships between the workpiece displacement and the contact deformations are obtained. Based on the static equilibrium equations, these equations are combined and linear equations are obtained to calculate the tangential contact forces between the workpiece and spherical-tipped fixture element. According to the maximum tangential contact force, the minimum clamping force to prevent slippage between the workpiece and spherical-tipped fixture elements is calculated. At last, this method is illustrated with a simulation example.

Abstract: This paper discusses burr in microdrilling that affect forms and functions of parts. The effects of microdrilling parameters on burr length and width are identified. The experiment was conducted using Mikrotools DT110 machine with one millimetre diameter of HSS on copper workpiece. Burr heights in terms of burr length and burr width were measured by using scanning electron microscope. The data was analyzed using Taguchi method to find the optimum micro-drilling process parameter for minimizing the burr height. The relationship among spindle speed, feed rate and burr has been developed. It is found that feed rate is the most influential factors on the burr height. The desirability of getting the minimum burr height is 72% and the optimum parameters are 30000 rpm spindle speed and 0.2 mm/min feed rate.

Abstract: Optical properties and microstructures of Mg(Zr0.05Ti0.95)O3 thin films prepared by sol-gel method on ITO/glass substrates at different amount of chelating agents and annealing temperatures have been investigated. The relative intensity ratio values of the peak Mg(Zr0.05Ti0.95)O3 thin films, secondary phase of MgTi2O5 and grain growth were depended on the amount of chelating agents and annealing temperature. In the optical transmission spectra, the Mg(Zr0.05Ti0.95)O3 thin films present high transparency (over 60%) in the visible region of the spectrum. The dependence of the optical properties and microstructure characteristics on thermal treatment was also investigated.

Abstract: In this paper, novel latent curing agents for epoxy acrylic resin a~e were synthesized and characterized with 1H NMR and MS in this study. Pot life of epoxy acrylic resins containing 3wt.% a~e or γ-aminopropyltrithoxysilane was compared in this paper and experiment data indicated that a~e were inactive in epoxy acrylic resin at room temperature. Curing temperature for double compositions resin is about 120°C and pot life at room temperature is longer than 6 months. The optimal curing condition for these curing agents were selected through several experiments.