Stanford Develops Carbon Nanotubes

Researchers at Stanford University have demonstrated the first functional computer constructed using only carbon nanotube transistors.

Scientists have been experimenting with transistors based on carbon nanotubes, or CNTs, as substitutes for silicon transistors, which may soon hit their physical limits.

The rudimentary CNT computer is said to run a simple operating system capable of multitasking, according to a synopsis of an article published in the journal Nature.

Made of 178 transistors, each containing between 10 and 200 carbon nanotubes, the computer can do four tasks summarized as instruction fetch, data fetch, arithmetic operation and write-back, and run two different programs concurrently.

The research team was led by Stanford professors Subhasish Mitra and H.S. Philip Wong.

“People have been talking about a new era of carbon nanotube electronics moving beyond silicon,” Mitra said in a statement. “But there have been few demonstrations of complete digital systems using [the] technology. Here is the proof.”

IBM last October said its scientists had placed more than 10,000 transistors made of nano-size tubes of carbon on a single chip. Previous efforts had yielded chips with just a few hundred carbon nanotubes.

Source

Websites ‘Leaking’ User Info To Other Firms

Many top websites share their visitors’ names, usernames or other personal information with their partners without alerting users and, in some cases, without knowing they’re doing it, according to a new study from Stanford University.

Many websites “leak” usernames to third-party advertising networks by including usernames in URLs that the ad networks can see in referrer headers, said the study, released Tuesday by Stanford Law School’s Center for Internet and Society. While there’s a debate in legal circles whether usernames are personal information, there’s a growing consensus among computer scientists that Web-based companies can use usernames to identify their owners, said Jonathan Mayer, a Stanford graduate student who led the study.

“The vast majority of usernames are unique,” he said. “Given the prevalence of social networking, often times, once you have a username for a social network, you then also have a person’s real name, possibly a photo, possibly more.”

Other websites share first names, email addresses and other information with advertising or other partners, Mayer said at a privacy conference in Washington. Those identifiers “get associated not just with what you’re doing right now, but get associated with what you’ve done in the past, and what Web browsing activity you may have in the future,” he said.

Source….