Prof. A. R. Mohanty

Question 1: Sir, you’ve worked in areas of vibration management and analysis and also machine fault detection. Could you elaborate upon the scope in these fields and their applications in the foreseeable future?

Answer: I’ll relate this to a human being. When we fall sick, we go to a doctor and they’d run tests, check our blood pressure, temperature and then try to diagnose what is wrong with us and give us medicine. Similarly, you can analyze the vibrations made by a machine and use that to tell what is wrong with them. This is known as machinery health monitoring or machinery condition monitoring, which happens to be one of my specializations.

People have been talking about intelligent machines, and with the vibratory information from a machine, one can do data analytics and monitor a gas turbine in Alaska from practically anywhere, from a smartphone in their lab. The example of such a machine in winter or a machine one kilometer deep in a Chinese mine makes evident that a lot of times it is not possible to physically take such data in situ and analyze it. This is the future of vibration analysis. With the advancements in electronics, sensors are becoming more capable of taking versatile and precise measurements, have larger data bandwidths, and making such machines wireless and integrating them with technologies of artificial intelligence, data analysis is the future of vibration analysis. A digital world with a mechanical front-end. [We cannot ignore the mechanical frontend, which is what my friends in machine learning are ignoring. If data is wrong, everything is wrong. We cannot violate laws of physics.]

Question 2: Could you tell us more about your ongoing research work in the usage of jute in noise isolation, and what are its ramifications in existing industries?

Answer: About a decade ago, we accidentally came across jute as gunny bag etc. We measured the acoustical properties of the jute fiber, and we were surprised by its very rich acoustical properties, comparable to existing materials such as fiberglass, which is very carcinogenic. Jute, in that sense, is green, natural, economic materials available. We started with that and have engineered jute materials to make boards out of them to block or absorb sounds, and we have been successful in implementing this in domestic refrigerators, and it is very cheap.

Today in the US, they use fiberglass panels at the backside of a refrigerator to reduce compressor noise. The same company took this technology from me and we implemented and demonstrated it at the cost of one dollar; we could significantly reduce the noise, by about 5 decibels. It is a very cheap technology, provided you engineer it. We have used it successfully in air conditioners, vacuum cleaners, engine enclosures and even in my old lab we used jute lining to enclose sound.

Follow up: Do you see it replacing other alternatives?

There is a technical catch here: Jute is a plant and it is driven by the economy of the country. It is mostly produced in and sold by West Bengal and Bangladesh and there is a cartel that manages the price. When we then had a demand for a million bales of jute from the US, they jacked up the price. So there’s no authority controlling the price plus the fact that it depends upon the weather conditions, etc, it's an iffy thing. Having said that throughout the world, e.g. in Brazil, southeast Asia, coconut fibers, papyrus fibers, banana leaves are used similarly because they have similar acoustical properties.

Question 3: What do you feel are the differences between the research environments in the University of Kentucky, Purdue University, and IIT Kharagpur?

Answer: Fortunately, being a graduate student at Kentucky and Purdue and being a master's level graduate student at IIT Kharagpur, let me tell you one major difference between the American and Indian education system; it is the home assignments which they give in the graduate programs in the US. You learn a lot from the assignments, which everyone takes very seriously. They are take-home types. The professor teaches similar to here, but it is the wholesome education in terms of doing it yourself and doing it in totality with all resources available. 20 years ago, resources were scarce in India compared to the US, but now, the resources in IIT and the resources at Kentucky or Purdue are at the same level. It is just whether we’re in the environment of doing everything on our own and doing extensive homework.

Question 4: You’re a member of the national committee on noise pollution control of the Control Pollution Control Board of the Government of India.

According to you, what are the simple technological measures needs to be taken to reduce noise pollution?

Answer: Recently, we’ve been working on what are called acoustical metamaterials. You must’ve seen highway barriers in Bombay, Delhi, etc where the large dwellings nearby aren’t affected by the highway noise. The screens in question here are very opaque, but the research which we’re going to implement pretty soon with the highway authority of India, our product doesn’t consist of a single sheet of material but they’re spaced so that light can pass through.

Question 5: You’re a member of multiple professional bodies, have multiple ongoing research and consultancy projects and manage an effective college routine on top of that. How difficult would you say this workload is for you to manage? Any productivity secrets you would like to share with us?

Answer: My productivity secret would be a good 8 hours of sleep. You might burn the midnight oil once in a while, but don’t make a habit out of it. Follow a routine life. To be productive, one advice that I’d give would be to sleep for a good 8 hours at night. By god’s grace, even today I get 8 hours of solid sleep, I don’t sleep in the afternoon. And make your workplace fun. I like to think of my equipment as my toys, and I like to play with my toys, and fortunately enough through IIT funding, I’ve been lucky or happy enough to have equipped my lab well to be one of the most populated noise or acoustics labs in the country, if not comparable to American standards, and I like playing with these toys, which is what keeps me going.

You have to be happy with what you do. You don’t have to work for an award or work to meet a deadline. You work at your pace, be happy with what you’re doing, and if you do not know, which I again tell my students, admit that you do not know. Even today, I would say I know nothing about acoustics, and even today I learn, which is very important. If you do not know, go back to the basics. In fact, on some days I still refer to the class 12 textbooks!

Question 6: Sir, an article (3 years ago) mentioned you working in a team of 40 professors of the mechanical department on a bullet train project being centered at IIT Kharagpur. Can you please elaborate on the outcomes of the project?

Answer: The bullet train is quite an ambitious project undertaken by the government consisting of several subsystems like CFD, suspension development, etc. I had been involved indirectly in this project and entrusted with the responsibility to look into the noise reduction. We had been working with the railways to apply the noise reduction techniques in the locomotive cabs. It is quite noteworthy that even today the noise inside the railway cabins of Rajdhani express is so high and harmful that the data could not be made public. We were quite fortunate enough that we got a locomotive from the railways for our experimentation in the railway workshop in Kharagpur for 10 whole days. However, the best part of all this was that we finally got to design our own locomotive which was manufactured in Jamshedpur and Varanasi. So, there is always the satisfaction when your own design and the work of students get recognized and such results are obtained. Further, we are working with the Shatabdi express and analyzing several of its parameters.

Question 7: After your prolific academic career ranging from NIT Rourkela to the University of Kentucky, Purdue University, what brought you to IIT Kharagpur?

Answer: It was all due to a huge family mishap that I had to travel back to help my family in India and believe me it was quite hard because I had to start all over from scratch, I had to leave behind well-paid job and a comfortable life back in the US. I started here as a visiting lecturer with a salary of a meager 2000/- per month whereas back there I was drawing out $6,000 while working for Ford. However, I carried on here because I had faith in my education which was further enhanced by the support of my friends and previous bosses. Now I stand here as content as I could be with so much in my hands from being a nobody in the department only through sheer work and without a single hint of regret in my decision.

Question 8: Sir, you have received many awards like the M.S Narayana Award and several others so how do you think they stand up as a motivation for you?

Answer: Let me put this out straight to you that I never work for an award, and no one else should. It is good to know that your peers recognize your hard work and it just gives you a huge feeling of self-satisfaction. I was quite happy when selected for the chair professorship where you are selected among your peers, so it was just satisfying that your colleagues recognize you. Further, I never aspire for an award, if it comes well and good and if not then obviously someone else was more deserving than you.

Question 9: You have a humongous teaching experience of nearly 30 years. What are some things about teaching and managing a college class that you think can only come with experience?

Answer: It is a very good question because now with the availability of Google at everyone’s fingertips, a teacher has to be very careful about what he speaks in the class which makes the job of a teacher very difficult nowadays. He can no longer blurt out fundamentals given in the textbook and just do the solved examples in the class as it can be done by the students themselves. However, teaching comes with experience, I teach my class with the help of stories and my own real-life experiences while making them connect with engineering. I try to do the same thing in all of my classes be it Machine Design or anything else. So the role of the teacher is to inspire the young minds and keep them excited about their subject. Another important point is that a teacher should never teach anything wrong as it harms everyone in the long run. So if one doesn’t know something then the one should be brave enough to stand out and admit his inadequacy. According to me, these are the most important traits of a teacher.

Question 10: What message would you like to give to the readers of Awaaz and people in general of IIT Kharagpur regarding the advent of the concept of acoustics and noise control? Would you like to give any tips to students interested in this field?

Answer: On a general note, I would like to address that God has provided us with a very valuable sensory organ, our ears, and one ought to protect them and treat them with care. Nowadays, it is required even much more with the increased usage of headphones which cause serious damage to them.

We have introduced Acoustics and Noise Control as an elective for the students, and the subject is more of an application-oriented one having a vast usage of the concept of physics like wave motion. So it is a great subject for those interested in wave physics, having knowledge of differential equations and knowing the basics of signal processing can be rest assured that it would be great for him.