June 6, 2011
Dr. Marahelli G. Prasad, Professor of Mechanical Engineering and Director of the Noise and Vibration Control Laboratory at Stevens Institute of Technology, has been invited to be a guest editor for a special issue of the journal, Advances in Acoustics and Vibration. The issue, titled "Noise Abatement for Industrial Machinery," will present research on reducing noise levels for psychological and physiological comfort. According to the National Institute for Occupational Safety and Health (NIOSH), "approximately thirty million workers are exposed on their job to noise levels that are potentially hazardous to their hearing." Sound waves produced by vibration, impact, friction, and fluid flow all lead to noise in industrial processes. With information for both researchers and practitioner, the issue will shed light on the latest research and methods for mitigating sound in industrial settings.
"It becomes an issue when noise is detrimental to hearing or becomes annoying," Dr. Prasad says. And elevated noise levels affect more than hearing. Excess noise can lead to elevated blood pressure and lost sleep, and can interfere with communications in the workplace, leading to accidents. Dr. Prasad notes that in addition, high noise levels can damage delicate equipment.
An expert in the field of acoustics and vibration, Dr. Prasad has spent over 30 years at Stevens working to minimize noise from machinery. He built the Noise and Vibration Control Laboratory at Stevens in 1984, installing anechoic and reverberation chambers to study sound waves, under a technical gift program of IBM Corporation, Poughkeepsie, NY. The Laboratory studies how sound propagates, measuring the sound field and using that information to design noise reduction techniques. The anechoic chamber simulates a free field by absorbing sound waves through high-density fiberglass wedges.
"In the chamber you hear true sound, without any echoes," Dr. Prasad explains. "This sort of information is very useful mathematically in designing ways to suppress sound." Recently, Dr. Prasad used Laboratory data to develop a new method for testing a muffler. With the appropriate mathematical data, Dr. Prasad was able to design a muffler on a computer and simulate its noise reduction digitally. "This simulation is very beneficial, because we didn't have to build the muffler in order to test it," he said. The resulting paper, "Acoustic Noise Synthesis for Duct Systems," appeared in Noise Control Engineering Journal.
At Stevens, Dr. Prasad has also worked to harness sound in order to produce energy. As a Senior Design team adviser, he mentored students in developing an Acoustic Energy Harvesting Device (AEH).The apparatus captures and amplifies sound waves, which are vibrations of air particles, in the same way that we are able to harness ocean waves for power. The team consisted of students Daniel DiClemente, Wan Muhammad Hafizuddin Wan Ahmad Ridzuan Azwa, and Mohd Aiman Abdul Jallil.
Advances in Acoustics and Vibration is the second journal that Dr. Prasad will edit in 2011. Earlier, he served as guest editor of the Journal of Aerospace Sciences and Technologies, which has also seen the publication of two of his invited papers.
Dr. Prasad notes that application for sound research, and study of acoustics and vibrations, extends far beyond mechanical engineering. "This is a field with a variety of applications," he says. "Civil Engineers find uses in building and construction. Electrical Engineers will work with speakers and amplifiers or electroacoustics. Mechanical Engineers are interested in the noise and vibration of machinery. Oceanographers deal with underwater acoustics. Artists will come at it with ideas of music production. There are many opportunities within the field for people from all areas of research."
About Dr. Marehalli G. Prasad
Dr. Prasad has made significant research contributions to the field of acoustics and vibration during his time at Stevens. His pioneering work on acoustical source characterization of sources in ducts using direct and indirect methods has important applications to muffler design. In 2006, he was elected a fellow of the Acoustical Society of America for his contributions to the acoustics of ducts and mufflers. In 2010, he was honored with the Bharat Gaurav (Pride of India) Award by the Indian International Friendship Society for his work in engineering and education. Dr. Prasad is also a Fellow of the American Society of Mechanical Engineers (ASME), and Acoustical Society of India (ASI). He is a board-certified member of the Institute of Noise Control Engineering (INCE), the Scientific Research Society Sigma Xi, and American Society of Engineering Education (ASEE). He is the faculty advisor for the student section of ASME and co-advisor for the student section of Engineers Without Borders (EWB). He has published over 100 papers, two of which have received awards, and made several invited presentations at national and international meetings. Under NSF International Travel Grants, he has presented papers in conferences in France, China, and India. He has worked as a Noise Control Expert for the United Nations Industrial Development Organization and chaired ASME Technical Committee on Duct Acoustics.