Today is ?-Day 2008. A day in honor of ?, one of the most important mathematical constants. It approximately equal to 3.14. ? represents the ratio of any circle’s circumference to its diameter in Euclidean geometry, which is the same as the ratio of a circle’s area to the square of its radius. For those who live in the US and use the MM/DD date representation format, the reason should be clear enough: March 14^th ? 3.14. On my knowledge the best ?-Day was in 1592 (3/14/1592 at 6:53:58 = 3.14159265358).

Coincidentally, ?-Day is also the birthday of Albert Einstein, who no doubt knew more than a little about ? :-)

14th March, 2008 3 Comments

For years, researchers have been building tiny nanobots that could one day serve a variety of purposes. But, until now, nanobots couldn’t work together. Recently, scientists Anirban Bandyopadhyay and Somobrata Acharya from the National Institute of Materials Science in Tsukuba, Japan, have built the first ultra-tiny, ultra-powerful “brain” for nanobots. The brain acts as tiny computer transistor. But instead of carrying out just one operation at a time, like a normal transistor, the new devices can simultaneously perform 16 operations at once. In other words, the devices use parallel processing—like the human brain—rather than serial processing (like a normal computer). The researchers call this ability “one-to-many” communication.

A machine assembly consisting of 17 identical molecules of 2,3,5,6-tetramethyl-1–4-benzoquinone (DRQ) executes 16 instructions at a time. A single DRQ is positioned at the center of a circular ring formed by 16 other DRQs, controlling their operation in parallel through hydrogen-bond channels. Each molecule is a logic machine and generates four instructions by rotating its alkyl groups. A single instruction executed by a scanning tunneling microscope tip on the central molecule can change decisions of 16 machines simultaneously, in four billion (4¹⁶) ways. This parallel communication represents a significant conceptual advance relative to today’s fastest processors, which execute only one instruction at a time.

Bandyopadhyay, A., Acharya, S. (2008). A 16-bit parallel processing in a molecular assembly. Proceedings of the National Academy of Sciences, 105(10), 3668-3672. DOI: 10.1073/pnas.0703105105

12th March, 2008 No Comments