Noise reduction coefficient

Engineering

Ecology

Biology

Materials science

Environmentally friendly

Absorption (acoustics)

Acoustics

Porosity

Waste management

Physics

Noise control

Process engineering

Composite material

Denim

Noise reduction

Pulp and paper industry

Applied Acoustics

Sound absorbing materials used for noise control is desired by the practitioners to be environment friendly and of low cost. This has motivated the researchers to look for alternate materials from natural sources. One step in this direction is exploring the use of recycled materials for potential application as sound absorbers. This paper identifies two materials, denim shoddy and waste jute fibers. They are characterized by their acoustical and physical properties. Experiments have been conducted as per 2-level 2-factor full factorial design of experiments. A comprehensive comparison of the sound absorption coefficients of denim shoddy and waste jute fibers, measured in an impedance tube and predicted by using empirical relations are shown. The absorption spectrum of these materials are compared with commercial glasswool with similar process parameters, and the results obtained show denim shoddy to be a better sound absorber than that of glasswool. A mathematical equation for Noise Reduction Coefficient is formed using the experimental results obtained and validated with a fresh set of experiments. Finally, economic comparison of these materials is conducted. The results obtained from technical and commercial research clearly states that the application of these materials for noise control will fetch better results apart from being cost-effective and environment-friendly.

Recycled materials as a potential replacement to synthetic sound absorbers: A study on denim shoddy and waste jute fibers