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Acoustics is a science that deals with the production, control, transmission, reception and effects of sound. Soft surfaces such as textiles absorb sound waves while hard surfaces like ceramic tiles gypsum tend to reflect sound waves causing ‘echo’. Dense, massive materials such as concrete or brick tend to transmit sound waves through the material. High frequency sound waves are not capable of being transmitted through massive and heavy materials. Low frequency sound waves are transmitted through massive materials. Millions of people are affected by noise pollution. Traffic noise may affect the ability to work, learn, rest, relax and sleep. Noise pollution can damage psychological health; can cause hypertension, high stress level, hearing loss, sleep disturbances, and other harmful effects. We can control traffic noise in our home by constructing a barrier wall, increasing the isolation quality of the home and controlling the noise directly at the source. Constructing the height of a barrier wall could result in a noticeable decrease in traffic noise. However, certain guidelines must be met for the effective wall; it must be solid with no penetrations in order to be effective. Sound Transmission Class (STC) is a common way of comparing sound in building; it describes the badly sound waves in the range of normal human voices i.e. 125 – 4000 Hz. Our aim is to improve the STC of a wall by constructing it from a more dense material by using sound absorbing material. STC and Sound Reduction Index (SRI) measurements are highly dependent on sound frequencies. Everyday materials have widely differing SRIs. A thin glass plate would have 20-25 dB, concrete slabs would have 40 dB and that of two brick walls separated by a large air would be 60-75 dB. Noise Reduction Coefficient (NRC) measures how much sound they can absorb. Acoustical material has been primarily applied to the specific purpose of providing high values of absorption and reduces the reverberate sound pressure levels and consequently the reduction of the reverberation time in enclosures. Recent advances in material science and nanotechnologies are producing significant improvements in the design, production and performance of acoustical materials. Foamed panels have higher natural flexural vibration frequencies than solid sheets of the same mass per unit area and have the ability to absorb impacts at a constant crushing load. Ceramic foams are used extensively in aerospace and aerogels (frozen smoke) have been used primarily in high-tech aerospace missions. If the diameters of the perforations are less than 0.3 mm, we can produce wide-ban absorbing materials. Our prime motto is to synthesize higher coefficient sound absorbing materials and compared it with the older absorbing materials.
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