Investigation on acoustical properties, thermal stabilities and water sorption abilities of finger millet straw fibers, darbha fibers and ripe bulrush fibers

Abstract

Finger Millet (Eleusine coracana) is a protein-rich plant popularly known as ragi in Karnataka. The literature cites many researchers studied the nutritive-value of its grains, kernels, and it's flour. And, few researchers tried to explore the utilization of the leftover plant for xylose production, briquet making, and so forth. Darbha (Desmostachya bipinnata) has been known popularly for its medicinal importance in the traditional Hindu society since Vedic times. The research was mainly focused on drug analysis, drug authentications, anti-inflammatory, antimicrobial, and analgesic potential of Darbha. Herein, the three readily available, commonly sourced and widely explored fiber types for their medicinal properties and nutritive gain are investigated for their sound absorption efficacies. The four types include finger millet (Eleusine coracana), darbha (Desmostachya bipinnata), and ripe bulrush fibers (Typha Domingensis). All fibers were monitored for their sound absorption properties, with sample thickness of 10 mm, in accordance with ISO − 10,534 (2). The effect of sample thickness on sound absorption behaviors of two fiber types yielding best results were performed by increasing the sample thickness to 20 mm. The two fiber types yielding best results were also monitored for their thermal stabilities, surface morphological characteristics and water sorption abilities. The effect of chemical treatment on the water absorption abilities and fiber surface morphologies on sound absorption abilities were also correlated. The combinatorial results drawn from the sound absorption coefficient measurements, thermal analysis and water sorption studies supports that peroxide treated finger millet straw fiber to be the best suitable fiber for noise reduction. Also, the observed appreciable sound absorption properties of peroxide treated finger millet straw fibers support their possible interior acoustical applications.