Application of a Multipole Secondary Source for Propeller Active Noise Control

Abstract

The commercial feasibility of active noise control (ANC) is very promising due to its capability beyond passive noise control (PNC). To some extent ANC becomes a complement of PNC. The active noise reduction is also capable and beneficial in reducing noise selectively. However, the active noise reduction using a conventional secondary source can become very complicated if a significant noise level reduction is required, since a large number of secondary sources will be needed. The active noise reduction is also less effective for reducing high-frequency noise. With such perspectives, a novel approach has been developed using a multipole secondary source to addressthe problems mentioned. In addition, the multipole secondary source will be used for numerical simulation of noise reduction in of propeller noise source in a free field.

The Effectiveness of Blended Learning as an Instructional Model in Vocational High School

“…The results of his research indicate that the blended learning model is effective to achieve the learning objectives set previously. Kusni (2008) This model incorporates face-to-face learning in the classroom with the web system via the internet outside the classroom as well as with the practice system, which allows increasing the quantity and quality of interaction between lecturers and students, hence the problem of overcrowding of lecture material can be overcome. In the implementation of blended learning here also includes practicum activities as a way to achieve learning objectives.…”