The threat of a nuclear explosion looms large over our planet. Any uncomfortable rise in geopolitical tensions brings to mind the possibility of nuclear war and its devastating consequences. The world got the extraordinarily bitter taste of atom bombs when they were dropped over the Japanese cities of Hiroshima and Nagasaki to close out the Second World War.
Fair to say, it’s a bleak prospect.
Though the hope is that a nuclear explosion never comes to pass, it is important to prepare for when it does occur. If that bomb goes off, do we have a way to reduce the effects of the blast?
Research scientist Dr Meera Chadha has put her mind to solving this problem. She has been at it for at least five years, gaining the mathematical know-how for investigating the problem in 2010. Her findings after years of research are remarkable – dust can come to our rescue.
Using mathematical modelling, Dr Chadha has shown that the deadly effects of nuclear weapons can be mitigated to some extent with the introduction of dust particles. The otherwise-irritating substance (allergic folks can testify) is found to reduce the energy released from the blast and curtail the distance over which damage can occur.
“The aim of the study was clear from the beginning,” Dr Chadha tells Swarajya. “To mitigate or reduce the effects of an explosion, like the one in Beirut, but a nuclear explosion in particular.”
Dr Chadha used the bombing of Hiroshima as a reference. That bomb had a yield of 15 kilotonnes and was dropped over the city from a height of more than half a kilometre. Flash burns were felt nearly 1 km away and buildings were destroyed over a 1.6 km radius.
“I thought that if I could reduce that 1.6 km radius and take it down to about 1 km or 1.2 km, we would be moving in the right direction,” she said contemplatively.
The Lie group of transformations, named after the Norwegian mathematician Sophus Lie, was Dr Chadha’s primary mathematical weapon of choice. She had picked up this technique during the time of her doctoral research, where she was studying the impact of dust particles on the strength of shock waves.
For her latest study, she had to take things up a notch.
“I wanted to add nuclear explosions in particular. The temperature is very high, going up to millions of degrees. Because of the high temperature, the air gets ionised in the vicinity of the blast. More temperature means more pressure. I took into account the rate of change of vibrational energy, added 5 per cent dust particles, and solved the problem with five equations,” says Dr Chadha, whose comfort with mathematics has been a nearly lifelong affair.
She found that the energy released and damage radius decreased with time as dust parameters increased. Put simply, the dust particles absorbed the shock. She published the finding in the Proceedings of the Royal Society A in June this year.
In the second round, not satisfied with 5 per cent dust, Dr Chadha decided to step up the quantity. “I framed a model where I added more dust particles. There I had to work through seven equations. I also had to take into account all the parameters of air and dust – density, pressure, temperature, and velocity. The study became extremely complicated,” she said.
But overall, the mathematical ingredients led to a satisfactory outcome. She recorded a substantial reduction in damage radius (over 40 per cent) and a reasonable reduction in pressure (about 10 per cent). This finding was published in another paper in the Journal of the Physical Society of Japan.
Dr Chadha is quick to emphasise that mathematical assumptions dictate the numbers obtained in the study. She says experiments conducted in a controlled environment could verify her claims and provide a realistic picture.
“I am glad that this study has garnered some attention,” says Dr Chadha. “The government should establish a mathematics research centre in the country. It should deal in pure and applied mathematics and on the link between them. Interdisciplinary research should be pursued.”
Research of the kind that Dr Chadha is engaged in demands high-performance computing. Fortunately, under the National Supercomputing Mission, supercomputers and related infrastructure are gradually percolating to different parts of the country.
Asked whether such technology would help, Dr Chadha says, “Yes, we are looking for support from the government. It would help us simulate this study. And not just this study, computing technology would help in the use of mathematics in various fields like medicine, traffic, and pollution.”
Science over circumstance
Dr Chadha has arrived at this potentially breakthrough result, but the journey has not been straightforward. Her story can serve as an inspiration for women and men in the STEM fields, namely, science, technology, engineering, and mathematics.
Though she was born in Lucknow, Dr Chadha was raised in Delhi. She completed her schooling as well as undergraduate and graduate training in mathematics in the capital.
After that, movement was an integral part of her life.
“In my final year of Master’s, I got married to an Army officer. Then we moved out of Delhi and I took up teaching jobs wherever I got the chance. We had to move every two and a half years,” she said.
As time went on, she taught mathematics to students of nearly all levels – from Class I to the Bachelor of Technology (BTech) course. At one institute, she even taught human values and professional ethics, while in another she helped impart personality development training.
“Here I was telling students that the sky's the limit and you can achieve anything. When you walk the talk, it’s easier to show the way. So the foundation was laid here.”
Over two decades later, Dr Chadha found stability once again. She returned to Delhi after her husband had taken voluntary retirement from the Indian Army. It was 2010 and she wanted to teach mathematics again. But a meeting with Professor Jasobanta Jena at Netaji Subhas Institute of Technology set her on a new path – a PhD in mathematics.
She was 40 years old and loving it. “I enjoyed research so much that I was absolutely addicted to it,” she says with great enthusiasm.
Four years in, Dr Chadha had submitted her thesis, and the next year, 2015, she had received her PhD degree.
Unfortunately, personal circumstances – an illness in the family – compelled her to take a break year. Still, she was not one to lose motivation.
“During this gap time, I did a lot of reading. I was thinking about what I could do with my PhD degree,” she said. “That’s when I came across this book called Science Towards Spirituality, which featured a conversation between a Jain saint and Dr A P J Abdul Kalam.”
A question posed by the Jain saint to the former president of India – whether it was possible for a peace-loving country like India to build a “cool bomb” that would nullify the effects of the atomic bomb – got her thinking.
Soon, she was spending long hours tackling the problem with what she knew best – mathematics.
Even as a teenager, Dr Chadha spent her assignment-free vacations solving Calculus problems. Now well into her adulthood, mathematics was once again energising her spirit during her year away from professional work.
“I had the support of my family too. This gave me confidence,” she says.
This still wasn’t enough. Dr Chadha needed to know how she could go about her research.
Around that time, she fortuitously learnt of a series of schemes to empower women scientists. These government schemes sought to bring gender parity to scientific research in India. Under one scheme in particular, called “WOS-A”, women scientists could pursue research in basic or applied sciences in frontier areas of science and engineering.
This was perfect for Dr Chadha, and she signed up for it. The rest, as they say, is history, but more accurately in Dr Chadha’s case, a whole lot of mathematics.
Today, Dr Chadha is enjoying her work as much as she did a decade ago when she enrolled in a PhD programme at the age of 40.
Would she have any advice for women professionals in science and technology?
“Do not have any mental barriers. Age is just a number. Don’t think I can only do this or that,” she says.
“Be yourself and pursue your dreams. Think big and dream bigger. Everyone has infinite potential. Just have a purpose in mind and work towards that purpose. That’s what I believe.”
True as the mathematics she does.
Karan Kamble writes on science and technology. He occasionally wears the hat of a video anchor for Swarajya's online video programmes.
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