Researchers at the University of Michigan are developing an advanced, smart sensor for recognizing and measuring airborne chemicals. The low-power consuming model can be used for detecting indicators of disease or chemical weapon vapors.
In gas detection processes, the chemicals are separated before being measured. However, in vapor mixtures individual chemicals cannot be identified easily. A professor in the University of Michigan’s Department of Biomedical Engineering, Xudong “Sherman” Fan, and other researchers at U-M and at the University of Missouri, has developed a better process for dividing the chemicals.
In conventional gas sensors, the gas is sent through two tubes in a sequential manner. Chemical vapors can be considered as tiny clouds that overlap in the gas. The first tube is coated with a polymer in the interior that reduces the speed of heavier molecules. The time duration for the travel provides information about the chemical. This gas is then sent through a second tube that has a polar polymer coating. This is charged with opposite charges at the ends. This polar coating reduces the speed of polar gas molecules, while other molecules pass through faster. This helps recognize the chemicals in the gas.
The new system includes a computer and a detector that observe the beginnings and ends of chemical clouds that are partially separated. It directs the compressor to run when a complete cloud is detected. This feature saves considerable power and can be used in remote locations.
Alternative tubes can be used for the second part as it takes a long time for analysis. A decision-maker decides on the distribution of gas between the secondary tubes. Tubes having different coatings and different lengths can be designed to separate specific gasses. Specific tubes can be designed to sense specific molecules, such as those in chemical weapon vapors.
The smart sensors have identified around 20 different chemicals in the gasses.
Source: http://www.umich.edu/