Portable gas sensors better chemical detection

Portable gas sensors for better chemical detection

6:08 AM, 8th May 2012
Portable gas sensors for better chemical detection
Xudong Sherman Fan, Professor, University of Michigan.

MICHIGAN, US: Portable gas sensors can allow to search for explosives, diagnose medical conditions through a patient’s breath, and decide whether it’s safe to stay in a mine. These devices do all this by identifying and measuring airborne chemicals, and a new, more sensitive, smart model is under development at the University of Michigan. The smart sensor could detect chemical weapon vapours or indicators of disease better than the current design. It also consumes less power, crucial for stretching battery life down a mineshaft or in isolated clinics.

The main advance of the sensor under development by Xudong Sherman Fan, Professor, University of Michigan, is a better approach to divvying up the chemicals. The researchers have demonstrated their concept on a table-top set-up, and they hope to produce a hand-held device in the future. In most gas sensors today, researchers separate the chemicals into smaller clouds by sending the gas through two tubes in sequence. A polymer coating on the inside of the first tube slows down heavier molecules, roughly separating the chemicals according to weight. The time it takes to get through the tube is the first clue to a chemical’s identity.

A pump and compressor collect gas from the first tube and then send it into the second tube at regular intervals. The second tube is typically coated with polar polymers, which are positively charged at one end and negatively charged at the other. This coating slows down polar gas molecules, allowing the non-polar molecules to pass through more quickly. With this second clue, the researchers can identify the chemicals in the gas.

The decision-maker added by Fan’s group consists of a detector and computer that watch for the beginnings and ends of partially separated chemical clouds. Under its direction, the compressor only runs when there is a complete cloud to send through. In addition to consuming one-tenth to one-hundredth of the energy expended by the compressor in typical systems, this approach makes data analysis easier by keeping all molecules of one type together, said Jing Liu, Graduate Student, University of Michigan.

Because no gas can enter the second tube until the previous chunk has gone all the way through, the smart system takes up to twice as long to fully analyze the gas. However, adding alternative tubes for the second leg of the journey can get the system up to speed. Then, the decision-maker acts like a telephone operator.

This way, the device never stops the flow of the gas from the first tube. These second tubes can be customized for separating specific gasses, made to various lengths and with different coatings. “If we have suspicion that there are chemical weapon vapours, then we send that particular batch of molecules to this hotline. It could identify them with really high sensitivity,” said Fan. Their smart sensors fully identified gasses contains up to 20 different chemicals, as well as compounds emitted by plants.

© University of Michigan News

0 Comments

Login

Your Comments (Up to 2000 characters)
Please respect our community and the integrity of its participants. WOC reserves the right to moderate and approve your comment.

Related News


Flour JV bags Tengizchevroil’s wellhead pressure project in Kazakhstan

IRVING, US: Fluor Corporation’s joint venture with WorleyParsons, the Kazakh Institute of Oil and Gas (KING) and KazGiproNefteTrans Engineering ...

Read more
Chevron Phillips plans two polyethylene facilities at Texas

THE WOODLANDS, US: Chevron Phillips Chemical Company plans two polyethylene facilities as part of the company’s US Gulf Coast (USGC) Petrochemic ...

Read more
BASF develops high-performance Neopor Plus

LUDWIGSHAFEN, GERMANY: BASF is continuously developing its Neopor (advanced version of the insulation classic Styropor) product range. With a declared ...

Read more
Indian specialty chemical industry shivers with dollar rise

SINGAPORE: The rise of the dollar against the rupee from Rs 50 to Rs 53.85 has led to a sudden slug in the Indian specialty chemical industry. Adding ...

Read more
Westlake withdraws proposal to acquire Georgia Gulf

HOUSTON, US: Westlake Chemical Corporation following acquisition discussions with Georgia Gulf’s management, notified Georgia Gulf that Westlake ...

Read more
BASF to build new formic acid plant in Geismar, Louisiana

FLORHAM PARK, US: BASF plans to build a state-of-the-art production plant for formic acid at its integrated “Verbund” site in Geismar, Lou ...

Read more