The current study is a bibliographic observation on prevailing tendencies in the development of acoustic absorption by natural fiber composites. Despite having less detrimental environmental effects and thorough availability, natural fibers are still unsuitable for wide implementation in industrial purposes. Some shortcomings such as the presence of moisture contents, thicker diameter, and lower antifungus quality hold up the progress of natural fiber composites in staying competitive with synthetic composites. The review indicates the importance of the pretreatment of fresh natural fiber to overcome these shortcomings. However, the pretreatment of natural fiber causes the removal of moisture contents which results in the decrease of its acoustic absorption performance. Incorporation of granular materials in treated fiber composite is expected to play a significant role as a replacement for moisture contents. This review aims to investigate the acoustic absorption behavior of natural fiber composites due to the incorporation of granular materials. It is intended that this review will provide an overview of the analytical approaches for the modeling of acoustic wave propagation through the natural fiber composites. The possible influential factors of fibers and grains were described in this study for the enhancement of low frequency acoustic absorption of the composites.

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A cross-sectional study was undertaken to determine the anthropometric profile and nutritional status of adult Kora Mudis, a tribal population of Bankura District, West Bengal, India, based on their body mass index (BMI). A total of 500 adult (18.0 < age ≤ 65.0 years) Kora Mudis from two villages (Phulberia and Siromonipur, approximately 160 km from Kolkata) were studied. Anthropometric measurements, including height, weight, circumferences, and skinfolds, were measured using standard protocols. BMI was calculated and utilized as a measure of nutritional status. The extent of undernutrition (BMI < 18.5) was found to be very high (52.2%). The frequency of undernutrition was higher in women (56.4%) than men (48.0%), although this difference was not statistically significant. Using the World Health Organization criterion, the prevalence of undernutrition is classified as 'very high'. In order to fully understand the causes and consequences of adult undernutrition, further research is needed not only among this ethnic group but also on the other tribal populations of India.

In this study, a new innovative fibro-granular composite was prepared as a natural acoustic material by combining fibrous and granular materials. Delany-Bazley model and Biot-Allard techniques were utilized to estimate the absorption coefficient of the developed composite material. The predicted values were validated through an analytical outcome employing Johnson-Champoux-Allard technique and an experimentally measured value which were conducted in an impedance tube. The outcomes showed the reflection of the good agreement between the analytical and experimental methods. The current research concluded that the introduction of granular materials provides significant contribution in enhancing the surface area within the composite, thereby achieving a promising acoustic absorption in the low-frequency region which is below 1 kHz. In addition, the current research also reports that, like Johnson-Champoux-Allard model, Delany-Bazley and Biot-Allard models are also two efficient analytical tools for predicting the significant low-frequency acoustic absorption performance of a fibro-granular composite.

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