Solar Loops and Space Weather
08-20-12
Paul M. Bellan, Professor of Applied Physics, and colleagues have reproduced plasma loops in the laboratory to help understand solar physics. "We're studying how these solar loops work, which contributes to the knowledge of space weather," says Professor Bellan, who compares the research to studying hurricanes. For example, you can't predict a hurricane unless you know more about the events that precede it, like high-pressure and low-pressure fronts. The same is true for solar flares. "It takes some time for the plasma to get to Earth from the sun, so it's possible that with more research, we could have up to a two-day warning period for massive solar flares." [Caltech Release] [E&S Article]
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Paul Bellan
Material's Spacing is Key to Brittle-to-ductile Transition
07-16-12
Julia R. Greer, her postdoctoral scholar Dr.Dongchan Jang, and colleagues have used experiments and atomistic simulations of nano-twinned metals (which have the unique combined effect of being strong and ductile) to decipher the specific role of the twin boundaries. They have found that it is the spacing between the twin boundaries that determines whether a material is brittle or ductile as opposed to the sample size, as would be expected. Greer states "this is probably the first study that truly isolated the twin boundaries by making samples which contained only twin boundaries, periodically spaced throughout the sample, and then tested them in tension. This understanding will help in the design of better structural materials and provide a certain amount of predictability in doing so, which has not been possible to date." [Nature Nanotechnology Article and Movies]
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Julia Greer
Dongchan Jang
postdocs
The Physics of Going Viral
06-28-12
Rob Phillips, Fred and Nancy Morris Professor of Biophysics and Biology, and colleagues have measured the rate of DNA transfer from viruses to bacteria. They wanted to find out whether pressure plays a dominant role in transferring the DNA. Instead, he says, "What we discovered is that the thing that mattered most was not the pressure in the bacteriophage, but how much DNA was in the bacterial cell." When the bacteriophages try to inject their DNA into the cells, the factor that limits the rate of transfer is how jam-packed those cells are. "In this case," Phillips says, "it had more to do with the recipient, and less to do with the pressure that had built up inside the phage." [Caltech Press Release]
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health
Rob Phillips
Plasmas Torn Apart
02-15-12
Using high-speed cameras to look at jets of plasma in the lab, Paul M. Bellan, Professor of Applied Physics, and colleagues have made a discovery that may be important in understanding phenomena like solar flares and in developing nuclear fusion as a future energy source. "Trying to understand nature by using engineering techniques is indeed a hallmark of the Division of Engineering and Applied Science at Caltech," says Ares Rosakis, Chair of the Engineering and Applied Science Division. [Caltech release] [Plasma movie]
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Paul Bellan
Accelerating Nanoscience out of the Laboratory and into the Marketplace
12-13-11
The Alliance for Nanosystems VLSI (very-large-scale-integration)—a collaboration between the Kavli Nanoscience Institute and Leti-Minatec in France—has launched its first start-up company. The Alliance, which began informally in 2005, was officially created in 2007 to transform academic, nanotechnology-based prototypes into robust, complex sensing systems and thus accelerate nanoscience out of the laboratory and into the marketplace. The start-up company, Analytical Pixels, will focus on the design, manufacture, and commercialization of multi-gas sensing systems created over the past five years in the field of nanoelectromechanical devices, read-out electronics, and system integration, and built on two decades of prior research carried out at Caltech. [Caltech Feature]
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Michael Roukes
Oskar Painter
KNI
![An argon plasma jet forms a rapidly growing corkscrew, known as a kink instability. [Credit: A. L. Moser and P. M. Bellan, Caltech ]](https://cloudfront.eas.caltech.edu/eas_news/images/613/thumb/plasma-bellon-release.jpg?1329342520)
