The quality of the communication between teachers and students and ultimately, of classroom education itself, is closely linked to the acoustic quality of the auditorium. This acoustic quality can be characterized based on the reverberation time (RT), speech transmission index (STI) and the sound insulation. In this context, an acoustic study was conducted in an auditorium located in the Higher...

The mining chute is an important equipment in the process of coal transportation and coal screening preparation. During the working process, the mining chute will generate a lot of vibration and noise because of constantly friction and impact of gangue and coal blocks. In order to reduce the vibration and noise during the operation of the chute, a new type of foam aluminum laminated structure i...

Vibrating machinery such as pumps, generators and compressors normally use passive insulation materials to reduce sound radiation. This paper provides a practical examination of possible solutions to active control of machine enclosures that reduces the radiated sound intensity from the enclosure to the environment. The results show that a combination of simple sky-hook type feedback controller...

Suppression of the transmission of undesired sound in ducts is a fundamental issue with wide applications in a great variety of scenarios. Yet the conventional ways of duct noise control have to rely on mismatched impedance or viscous dissipation, leading the ducts to have ventilation capability weakened by inserted absorbers or a thick shell to accommodate bulky resonators. Here we present a m...