Active Noise Control using Variable step-size Griffiths’ LMS (VGLMS) algorithm on Real-Time platform

This paper proposes implementation of Griffith’s Variable step-size algorithm for Active Noise Control (ANC) on ADSP-TS201 EZ-Kit Lite. The dual computational units and execution of up to four instructions per cycle which are special features over other processors are best utilized to generate an optimized code. The VGLMS provides improved secondary path estimation and computations involved are marginal as the same gradient is used for step-size computation and coefficient adaptation. The improved secondary path estimate, in turn improves the ANC performance. Further, variable step-size algorithm is used for the main-path to achieve faster convergence. Both for narrowband (fundamental and its harmonics) and broadband noise fields, for a duct the attenuation achieved is 25 dB and 15 dB respectively. The program execution time was only 1.25% for an input sampling rate of 1 KHz which indicates the utility of the special features of the processor considered. Further these features have enabled in bringing down the program memory requirement in the implementation of the algorithm

Study on Mechanical Behaviour of Surface treated Coir Fiber Reinforced Polymer Matrix Composites

The need to pursue an environmentally safer future has prompted the researchers to look beyond the artificial or synthetic fibre based composites and engage in putting more thought into the utilisation of natural fibre based polymer composites. Although synthetic fibres have a lot of advantages but we can owe its declining use in recent years to its high initial cost, non bio-degradability, non -renewability , high energy consumption in manufacturing process and adverse environmental impacts. Natural fibres however more than compensate for their poor compatibility with the matrix, inherent high moisture absorption rate with their positive attributes like low cost, low density , non abrasivity, good thermal properties, enhanced energy recovery and bio degradability. Coir is an important lignocellulose fibre used for making variety of floor furnishing materials, yarn, rope etc. but they contribute to a very small percentage production of coir. So researchers are trying to find new areas for utilisation of coir as in reinforcement polymer composite. The present work deals with development and characterisation of coir fibre reinforced epoxy composites. The coir used in the composite is first treated with alkali (in varying concentrations and considering different time constraints for each composite) to improve its surface properties and improve its adhesion with the matrix. The mechanical properties of the composite such as tensile strength, flexural strength and hardness are tested. Finally SEM has been done to get a qualitative overview of the fractured surface and to understand the surface morphology better