Narrow Results

This paper describes the novel mathematical modeling of the 3-phase induction motor, various operations and study of its dynamic behavior and regenerative braking based on the model. This model uses v/f scheme to apply braking operation with the energy flow to the supply system instead of wasting the energy in braking resistor. It discusses the theory of induction motors, which is explored through both equations and computer simulation model using SIMULINK. The model also helps to study the behavior of the motor during its starting and load variation. The results from the analysis prove the demonstration of regenerative braking and the dynamic behavior and can give an opportunity to learn the different characteristics during these conditions.

Each rapid prototyping (RP) process has its special and unique advantages and disadvantages. The chapter presents a state-of-the-art study of RP technologies and classifies broadly all the different types of rapid prototyping methods. Subsequently, the fundamental principles and technological limitations of different methods of RP will be closely examined. Comparison of the present and ultimate performance of the rapid prototyping processes will be made so as to highlight the possibility of future improvements for a new generation of RP system.

This paper presents problem-solving strategies that Singapore students (n = 1002) used to solve three word problems on speed and the errors they made. It is surprising to find that the Primary 6 students performed significantly better than the Secondary 1 and Secondary 2 students, while the performance differences between the last two groups were not significant. The strategy analyses reveal that the Primary 6 students could use the arithmetic strategies, model method, and guess-and-check method more successfully than the secondary students. More effort needs to be made to bridge the gap between primary and secondary mathematics, and more word problems on speed need to be included in textbooks used in secondary levels.