Applied Mechanics and Materials Vols. 157-158

Abstract: This study introduces rotary ultrasonic face milling (RUFM) process into flat surface machining of K9 glass. The effective cutting velocity, and cutting length of single diamond particle were presented in RUFM. The model of material removal for RUFM was developed through examining indentation fracture mechanics theory and material removal characteristics of brittle materials, and analyzing kinematics properties of diamond grits in RUFM. With a view of comparative researches, the cutting force of RUFM and diamond milling of K9 glass are compared. The experimental results tell that the relationship between the cutting depth (dc) and the ultrasonic amplitude (A) of the cutter has remarkable effects on cutting force, which was also discussed in the kinematic characteristics analysis section. The results also show that RUFM process can significantly reduce cutting force and the effects of process variable changes on cutting force in RUFM are weaker as dc is smaller than A. However, the reduction trends of the cutting forces in RUFM are very small and even increased in some process conditions, as dc is larger than A. It suggests that the cutting depth should be smaller than the ultrasonic amplitude of the cutter with RUFM process to obtain better processing performance.

Abstract: Dissolved organic matter (DOM) in water from eutrophic water source was isolated into four classes as hydrophilic substances (HIS), hydrophobic acids (HOA), hydrophobic neutrals (HON), and hydrophobic bases (HOB). The formation of Trihalomethanes (THMs) and Haloacetic acids (HAAs) in chlorination of different DOM fractions was evaluated. The dominate species of THMs and HAAs were chloroform (CF) and trichloroacetic acid (TCAA) in the chlorination of raw water. There were close linear relationship between THMs/HAAs yields and SUVA254 values. Increasing of contact time and chlorine dosage enhanced the formation of THMs/HAAs yields from different DOM fractions. The increase of pH leads to more formation of THMs, and the highest production of HAAs was observed at pH 7.

Abstract: Belt conveyor is main transportation in coal-fired power plants. The traditional static design method that considering less actual working condition is main method in designing belt conveyor, and the method using the virtual prototype technology to design product can save cost while improving efficiency, but also use dynamics method to improve products. Build belt conveyor basic system that based on a certain type of belt conveyor, it is accomplished by using simulation software and conveyor belt discretization method. It can be obtained that virtual prototype technology is feasible and effective in belt conveyor dynamic design. By discussing the tension characteristics of belt conveyor, obtain the position of maximum tension and the tension distribution which have guiding significance for designing and maintaining belt conveyor.

Abstract: To solve the technical difficult problem of difficult-to-draw materials, this work presented a composite ultrasonic vibration system with variable cross-section rods. The four-terminal network method and the finite element method were used to design the conical, the exponential and the catenary transducers. The finite element results of show that the oval trajectory can effectively improve the friction effect between the wire and the tool head. The experimental result showed that the maximum amplitude was about 60 μm. It was 3 times of that in our previous work. These results demonstrated the design of the composite ultrasonic vibration system was feasible.