September R&D Round UpSeptember 3, 2010 By: Melanie Martella, Sensors
This month we have the ability to measure yoctonewton forces, a better information system for motorcycle cops, and a chemical sensor made of graphene and DNA.
Measuring Teeny, Tiny Forces
In its latest advance in measuring incredibly small forces, physicists M.J. Biercuk and H. Uys, working at NIST have created a sensor capable of measuring forces to one yocotonewton, or 1 x 10–24 Newtons, The sensor consists of a single crystal of beryllium ions placed inside a copper vacuum chamber (trap). A UV laser cools the ions down to spitting distance of absolute zero (and can I just say that I think it's insanely clever that you can zap something with a laser to cool it down?). Then, an electric field is applied, which will alter the degree of ion motion in the crystal. The more force applied, the more the ions will rock back and forth, causing the reflected laser light to rock back and forth in sync. Luckily, you can measure the effect on the laser light and use that to calculate how much force has been applied. In the experiments (and for more detail, I'd advise you to read the article "Yikes! NIST Sensor Measures Yoctonewton Forces Fast") the researchers found that they could measure 390 yoctonewtons in 1 s. Potential applications include force microscopy, testing physics theories, and for nanoscale science.
Better Information for Motorcycle Police
Driving a vehicle and contending with multiple information streams is challenging at any time but if you're a motorcycle officer responding to an urgent call, it's even more so. An EU-funded project called MoveOn aims to help by creating a multimodal, multisensor, zero-distraction interaction interface. As described in the article, "New technology for multi-tasking motorcycle officers" the researchers studied how motorcycle police officers operated to understand how the officers worked and the kinds of information demands they had and the best way to provide it. The MoveOn helmet provides voice control and is coupled to a jacket containing sensors and a processor. Data on the driver's stress level and environment are used by the system to decide what information to provide, and which channel (auditory, visual, or tactile) will be most useful; it also can cut off communications if it deems the officer too busy driving.
In an elegant piece of science, A T Charlie Johnson, Ye Lu, Brett Goldsmith, and Nick Kybert of the University of Pennsylvania have created a simple chemical sensor out of DNA-coated graphene. Starting with graphene transistors, the researchers soaked the transistors in a solution of specific single-stranded DNA-chosen based on its ability to act as a chemical sensitizing agent. The resulting sensor reacts with a given chemical and experiences a resistance change in the graphene. Because the change can be as large as 50%, the results are easy to detect and measure; it's also fast. According to the PhysicsWorld.com article, "DNA helps turn graphene into a chemical sensor", the sensor can give a response in <10 s and recover in about 30 s. The researchers posit that an array of suitable DNA-doped graphene transistors could be used to identify explosives, chemical weapons, or toxic compounds.
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