A Study on Acoustic Property of Composites from Waste Tyres

The basic aim in using the waste is to reduce the level of pollution that harms the environment. However a proper approach to manage waste or reduce the level of waste helps in conservation of resources for the succeeding generation and contributes to a healthy, clean and pollution free environment. In recent years, control on two major ecological issues such as waste disposal and noise pollution can help in achieving a green and healthier environment. For disposal, waste tires are normally burnt. Extinguishing fire from tire is very difficult. The fire develops a thick, dark smoke which contains CO2, SO2, cyanide, and products of butadiene & styrene. This study focuses on the fabrication of composites from epoxy-waste tire crumb by hand lay-up method and the investigation of its acoustical property by Impedance tube method using LABVIEW. In the present work three different materials such as PVC, Stainless Steel and Glass has been used to prepare impedance tube as per ASTM standards. All the sound testing has carried out at a frequency range of 500 Hz to 5000 Hz. This study clearly shows a promising waste management for tyres by developing a cost effective composite and thus contributing to a sustainable waste granule (waste tyre) reinforced polymer composite industry.

Utilization of Styrofoam ss Soundproofing Material with Auditory Frequency Range

One of preventive action methods of hearing loss that number tend to increase is by using brick that made from Styrofoam which is expected to have the ability as a soundproof that can be used to control the noise. The aim of this research is to assess the use of sound absorption material in which utilizing Styrofoam to reduce the noise exposure. In this study, cement and find aggregate that contain the Styrofoam and sand are mixed with the composition 1:4 and 1:6 and also by adding the polystyrene waste as much as 0%, 20%, 40%, 60%, and 80%. To determine the acoustical property of the mixture, the sound absorbing coefficient (α) was determined by using Four Microphones Impedance Tube (ISO 140-3). The results showed that the highest absorption coefficient value was at frequency 800 Hz by adding 80% Styrofoam for the composition of 1:4 at 0.4100 dB and at the frequency 800 Hz by adding 40% Styrofoam for the composition 1:6 at 0.5870 dB. Based on the results of this research, further study to potentially use Styrofoam as noise barrier is suggested.

Ultrasonic Assisted Synthesis, Acoustical Property and Antibacterial Activity of some Schiff Bases

An efficient, simple clean synthesis of Schiff bases of some 4-nitroaniline/ 2,4-dinitroaniline/ 3,4-dichloroaniline / 4-methoxy-3-nitro aniline with 3-bromo-4-fluorobenzaldehyde were done by an ultrasound irradiation method. The major advantages of ultra-sonication are short reaction time, operational simplicity, high yield, easy workup and environment friendly procedure. The isolated compounds obtained by ultrasound irradiation method were characterized by UV, IR and NMR spectral data. These acoustical parameters were determined. Furthermore their antibacterial activities are screened against certain strains of bacteria and showed significant anti-microbial activity.

Study of the Acoustical Mechanism of Nonwovens by Rank Method

Air permeability and acoustical behavior of nonwovens are two properties which are correlated with each other. And both are determined by the structural parameters of nonwovens. However, the structure of nonwovens is nonlinear, and the influences of parameters are out-of-order, that traditional methods can hardly characterize it. In this paper, the rank method is implemented to investigate the influence of structural parameters on acoustical property. Thus the mechanism of acoustical property of nonwovens is studied.

A Standing Wave-Duct System for Acoustical Property Prediction of Multi-Layered Noise Control Materials

Based on a hybrid transfer-matrix method, a new standing wave-duct system with four microphones for acoustical property prediction of multi-layered noise control materials is developed in this paper. In this system, the two-load method (TLM) and two-cavity method (TCM) are used for computing the transfer matrix of each material sample. The transfer matrices saved in a database in the system hardisk may be selected for predicting both the absorption ratio and transmission loss of a multi-layered treatment of materials. Verification results suggest that the newly designed standing wave-duct system is effective for acoustical prediction of multilayer material configurations.

Development of a Standing Wave-Tube System for Acoustical Property Measurement of Sound Absorption Materials Used on Vehicles

A standing wave-tube system for acoustical property measurement of vehicle-used sound absorption materials is developed in this paper. Theoretically, the standing wave ratio method and the two-cavity method with two-microphone configurations are combined and applied for calculating some acoustical parameters, such as sound absorption ratio, reflection coefficient, characteristic impedance, propagation constant, of a sample material. Based on the combined method, the standing wave-tube system including two microphones, an A/D board, a signal amplifier, a DSP computer and a set of software is carefully designed and performed. The verification results suggest that the newly designed system is accurate for acoustical property measurement of the materials used on vehicles. It can be directly used for selecting noise-control materials in vehicle acoustical designs.