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September 29, 1999


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Based On Some Sound Physics

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Sonia Chopra

Dipen Sinha When he was six years old, read a book called the Twelve Suns about 12 famous scientists.

There was one particularly interesting tale about a scientist who used up all his funds to conduct his research at home. He had no money to buy wood for the furnace. It was winter, it was bitterly cold and his wife was sick and hungry.

However, as his wife watched, he tore off the wooden frame of the bedroom, with the cold wind blowing and put it in the furnace. It worked.

"I was simply awed and dumbstruck. It was so moving that it etched into my memory deeply. Then and there I decided to become a scientist -- a physicist," said Sinha who grew up in a small mining town in Bihar and was home-schooled for the first few years. He does not remember the name of the scientist who was his inspiration, but the passion the book kindled in him remains.

Sinha, 48, is today a scientist at the Los Alamos National Laboratory and has won many accolades for his work.

Seven years ago, he developed and patented a technique, called Swept Frequency Acoustic Interferometry, that can be used to measure these properties of liquids from outside a container accurately in less than 30 seconds. Since every liquid has its unique sound speed, sound loss, and density, one can now identify a chemical if all these properties can be measured at the same time.

Sinha put sensors for these into a small portable instrument that law enforcement and other government inspectors can use to rapidly screen suspect containers to deter terrorism and other illegal activities.

He explained his technique: "How does one identify a liquid (chemical) that is hidden inside a sealed metal container without opening it? Standard optical, microwave, etc., techniques cannot be used because neither light nor electromagnetic waves would penetrate the walls."

It turns out that there is a way by using sound because high-frequency sound waves can get inside the container easily and interact with the chemical inside. Through a liquid, sound vibrations move with a certain speed that depends on the liquid.

This technique has many uses in industry and biomedical field. Sinha's patents cover a broad range of such applications.

Although originally developed for defense applications such as checking on chemical weapons and verifying the terms of scientific treaties were followed, it now has many civilian applications. For this, he won the received the Popular Science 100 Award in 1992. Three years ago, Sinha was awarded the Distinguished Performance Award by the Los Alamos National Laboratory for his seminal contributions in developing new techniques in non-destructive evaluation. He also has eight patents granted, six pending and has published 60 papers in various areas.

Sinha had also received a Research & Development Award for developing a solid state nitrogen dioxide sensor in 1990.

His journey to success has been one with few obstacles. Sinha's mother taught him for a few years because there were no kindergarten close by.

"I can still remember the day my mother taught me to write on a slate using a chalk. It was so exciting," Sinha said. "I also remember my dad taking me to elementary and middle schools where they gave me tests. I guess I passed because they kept moving me to upper levels."

As a result of moving so quickly, Sinha finished high school with the highest score in his entire district when he was 14. After that he went to St Xavier's College in Ranchi where he completed his B Sc with honors in physics when he was 18. He went on to earn a M Sc in physics at the Indian Institute of Technology, Kharagpur, with a post-graduate diploma in industrial physics.

In 1972, Sinha was granted admission at eight prestigious universities in the US. But he decided to do his Ph D at IIT. The following year, however, he changed his mind because all his friends had enrolled in American schools. But by the time, he decided to reapply it was too late to get into any of the schools he had turned down.

Fate intervened. He ran into two American physics professors touring India. They interviewed him and he received an offer to study at Portland State University in Oregon without even applying to the school.

"I had two weeks to get my visa, plane ticket and get on the plane... Although this was definitely not the among the best schools... it was the best decision I had made. It changed my life," Sinha said.

After he graduated from PSU, he did his postdoctoral fellowship at the Los Alamos National Laboratory. It was a position he got because of the papers he published on liquid helium.

The three years he spent in Los Alamos "were the most exciting of his life". By then, he had married a classmate, Barbara, also a physicist. But since she could get a fellowship at Los Alamos, the couple moved to California hoping to find satisfying jobs. Sinha soon found a job as a senior scientist at the Rockwell International Corporation in Anaheim. But he wished he had not taken it.

"I missed doing research terribly and did not enjoy the way a defense industry operated," Sinha said. Meanwhile, their only child Naveen was born and Barbara decided to stay home to take care of the baby.

Dipen Sinha Desperate to return to Los Alamos, Sinha applied for a job as a computer programmer. "I was asked to come for an interview and the physicist interviewing me thought I was crazy. He sent me over to another department to talk to them and I got hired as a physicist," said Sinha, who has been part of the same department for 13 years now.

Sinha's future ambitions and ideas are big.

"I have too many ideas but so little time to do everything. If I had the free time, I could invent one new thing every week," he said.

"I would like to find a group of like-minded people who could form a brain trust so that we can simply enjoy inventing things and finding solutions that can help solve major problem sin the world, like poverty, diseases, earthquakes and hurricanes made preventable," he says. "I hope this is done before I die."

Sinha's son, Naveen, 14, was recently named among the 40 finalists in the Discovery Talent Contest to be held in October in Washington.

"I look up to my dad for his achievements and innovative techniques. Every day he goes to work to develop and research his many ideas. I appreciate how my dad works so hard to help others and me," Naveen said.

"Whether it is a science fair project or a school assignment, he is determined to help me in any way he can. I think it is praiseworthy how he shares what he learns with me. I will be a scientist too, so I can tell him what new discoveries I have made. Then I will be closer to repaying my dad for the things he does for me."


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