The purpose of this study is to examine the effects of blended e-learning on electrical machinery performance (achievement test and self-assessment). Participants were two classes of 11th graders majoring in electrical engineering and taking the electrical machinery class at a vocational high school in Taiwan. The participants were randomly selected and assigned to either the experimental group (n = 33) which studied through blended e-learning or the control group (n = 32) which studied through traditional classroom learning. The experiment lasted for five weeks. The results showed that (a) there were no significant differences in achievement test scores between blended elearning and traditional learning; (b) students in the experimental group obtained significantly higher scores on self-assessment than students in the control group; (c) students' scores on self-assessment were significantly higher after studying through blended e-learning than before. Overall, blended e-learning did not significantly affect students' achievement test scores, but significantly affected their self-assessment scores.

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The acoustic horn plays a very vital part in high energy ultrasonic machining, and its design is critical to the quality and the efficiency of machining. This paper performs the analysis and design of acoustic horns for ultrasonic machining by employing ANSYS finite element software. Firstly, the theoretical dimensions of the horns are calculated and compared to three commercial available horns with different shapes. Moreover, their natural frequencies and amplitudes are obtained through the simulations of ANSYS. Finally, the numerical results are compared with commercial available horns.