Abstract
This article reports a study on the effect of different natural fibres, their blend ratios and varying air gaps between a needle-punched non-woven fabric and polystyrene backing on the sound absorption coefficients of the needle-punched non-woven fabrics. These parameters as well as their interactive effects were studied by variance analysis. The air gap varied from 0 to 25 mm in 5 mm increments; three natural fibre types (agave, flax and waste wool) were used; each one blended with polyester fibres in three blending ratios. The univariate test of significance showed that all three parameters and two of the three two-way interactions effects on sound absorption coefficients were significant. Only two-way interaction effect between blend ratio and air gap on sound absorption coefficient was not significant. It was found that the sound absorption coefficients increased with an increase in air gap size up to 15 mm, after which they decreased slightly as the air gap was increased further to 25 mm. In addition, the non-woven fabrics produced from the blend of waste wool and polyester fibres achieved the highest sound absorption coefficients than those of the other two natural fibres, and generally, the sound absorption coefficients increased with the increase in polyester fibre content in each blend studied.
Highlights
Excessive noise pollution is a problem in modern society
The only two-way interaction effect that failed to achieve significant effect on sound absorption coefficient at 95% confidence interval was between blend ratio and air gap; the P-value is low enough to achieve significance at 90% confidence interval
The univariate test for significance showed that all the parameters as well as two of three two-way interactions showed significant effects on measured sound absorption coefficients
Summary
Excessive noise pollution is a problem in modern society. The negative effects on human health and social environments due to noise pollution have been extensively studied and are well reported.[1] The main effects of noise pollution include noise-induced hearing impairment, interference with speech communication, disturbance during rest and sleep, adverse effects on psycho-social behaviour and mentalhealth performance as well as effects on residential behaviour and annoyance.[1] many methods have been devised to mitigate these problems. Various methods for reducing noise in the source–transmission–receiver system setup are available, but treating the transmission element is usually the most viable approach. It is not always difficult or unviable to treat the other two elements, that is, source and receiver
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