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Investigation of Effect of Muffler Performance on Environmental Pollutants
, M.Sc. Thesis Sharif University of Technology ; Nouri-Borujerdi, Ali (Supervisor)
Abstract
The silencer is used to reduce sound in the vehicle, air conditioning channels, power plants and guns. Functional parameters of the sound amplifier are the amount of noise reduction and pressure drop. There are few studies on the flow and pressure distribution in the silencer, and there is no article about the effect of the size of the internal passages on the pressure drop and acoustical performance of the silencer. Few studies have been done on the effect of the absorbent fiber diameter on the acoustic performance of silencer. In this study, the effect of different shapes of internal channels (extended tubes, baffles and number of chambers) on the pressure drop and acoustic performance of...
Investigating the Penetration and Reflection of Sound Waves from Polymers and Foams; the Behavior of A Polymer-Based Material Under Sound Waves in Water
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor) ; Assempour, Ahmad (Supervisor)
Abstract
With the expansion of global trade and economy and, in parallel, with the development of maritime transport, noise pollution caused by the sounds emitted by ships, vessels, submarines and offshore turbines threatens the environment of marine life. In addition, with the development of maritime weaponry, the need to cover the submarines with materials that reduce the reflection of sonar waves and absorbs them to provide acoustic stealth is felt more. Considering the focus of the most of the researches on the second topic and its practical importance, the present research is also in the same direction. The main goal of this project is to study the acoustic behavior of a polymer-based porous...