December 6, 2013
NASA Lends A Hand In Sifting Through Nanoparticles
John P. Millis, PhD for redOrbit.com - Your Universe Online
Although the name sounds like something out of a science fiction novel, nanoparticles are nothing more than tiny fragments of matter that are typically less than 100 nanometers in diameter – roughly one-thousandth the thickness of a sheet of paper. Despite their size, however, they can pose a significant health risk.
Arising from various industrial processes, some pollutants, and even volcanic activity, the small size of the particles – also called ultrafines – allows them to slide in between the cells of our organs if inhaled. Since human exposure to these particles has historically been low, our bodies have not developed an efficient immune response to them, which can lead to various health problems.
Moreover, nanoparticles are known to cause mechanical failures. As the ultrafines are entrapped in machinery, the efficiency and overall integrity of the equipment could be at risk. This is especially true where there is a lack of filtration systems available to scrub the air, so to speak.
As a result, scientists are finding it increasingly important to have a cheap and reliable way to identify and quantify the particles. Traditional methods for such studies are not very useful, however, because the equipment is bulky, inefficient and expensive.
Luckily, researchers at NASA’s Glenn Research Center have already been thinking about this problem. Since there is significant interest in the scientific community in measuring nanoparticles in space, the team was already working to scale down the heavy, inefficient equipment, into a device that could be deployed on spacecraft.
There are several technical challenges that the team has faced, however. The greatest of these hurdles is the issue of size. The primary reason why previous detectors were so large is that this allowed the device to sample a large number of particles in a short amount of time.
These systems had another major problem: efficiency. The machines worked by charging the particles as they entered the device and then using an electric field to sort the individual samples by their charge-to-mass ratio. But lacking efficiency, these large machines were only able to charge – and therefore analyze – about 7% of the particles. So while the new device, which measures a mere three-inches, lacks the volume of previous classifiers, this deficit is overcome with an impressive 90% charging efficiency.
Furthermore, the team also made significant advancements in the data analysis system. Once the particles are sorted, an algorithm is needed that can calculate the various properties of the particles and display the information on an LED screen.
While the NASA team was specifically designing this instrument for use onboard space exploration vehicles, the technology has already been licensed to Minnesota-based TSI Inc. for development of commercial use. There is still much to learn about ultrafines, but this work will go a long way towards making industrial processing safer for workers.