Developments to Watch
Slivers of Carbon That Could Break a Chip's Fever
Chips sprouting hairs? IT'S not such a fuzzy notion. Two University of Pennsylvania researchers believe ultraslim hairs of carbon might be the best way to cool down overheated silicon chips.
Electrons whizzing through ever-smaller wires on chips are generating a growing problem: heat. Better cooling methods could be vital for tomorrow's shrunken circuits, and carbon nanotubes might be just the ticket, according to Penn scientists A.T. Johnson and John E. Fischer.
In fact, nanotubes could be the best heat-transfer material there is. These teensy tubes of pure carbon--only 1/10,000th the width of a human hair--are "roughly 10 times better at conducting heat than anything else," says Johnson. In the Sept. 8 issue of Science, the two scientists report that heat flows through the nanotubes at an amazing 10,000 meters per second.
Embedding nanotubes in a chip's plastic or ceramic housing could create tiny "heat stacks" to cool the circuitry inside. The tubes might also be used to cool motor parts or the leading edges of airplane wings.By Otis Port; Edited by Catherine ArnstReturn to top
Teaching Rocket Scientists a New Trick
Two recent graduates of Ohio State University have developed a new way to make low-cost, wear-resistant ceramic parts for rockets. The process, devised as a senior thesis project by Raymond R. Unocic and Matthew B. Dickerson, both 22, has drawn attention from the U.S. Air Force and aerospace firms, and won a Collegiate Inventors Competition award.
This process could be ideal for manufacturing liners for the nozzles of solid-fuel rockets. Today, heavy tungsten liners are used to protect the nozzles. As fuel burns, the housing must endure temperatures as high as 2700 centigrade. Over time the liner wears away and rocket performance suffers. Non-oxide ceramics would be lighter and tougher than tungsten, but such materials are now produced in high-pressure furnaces at prohibitive cost.
The researchers simplified the process by forming a shape out of tungsten carbide and infiltrating it with a copper zirconium alloy. The result is a ceramic matrix of zirconium carbide with tungsten metal evenly dispersed throughout, says Unocic. The copper lowers the processing temperature and then bleeds out, leaving the zirconium structure behind. The composite can withstand temperatures up to 3000 C.By Neil Gross; Edited by Catherine ArnstReturn to top
Needle-free Injections: This Won't Hurt a Bit
As any diabetic can confirm, needles hurt. While there are devices for needle-free and painless injections, they cost about $300 each. Now, Medi-Ject Corp. has come up with a disposable version that promises to be financially as well as physically painless. Dr. Frank Pass, chief executive of Medi-Ject, says the device, which has yet to be clinically tested, will likely be packaged with the drug at little extra cost.
The new devices are essentially smaller and simpler versions of the company's present needleless injector. They deliver a spray of insulin or other drugs through micro-fine openings in the tip of needle-free syringes. Medi-Ject has sold its pricier injector for more than a decade, but in the U.S. only about 1% of diabetics use them. The company believes the cheaper device will be much more popular, and could be welcomed by nondiabetics as well. In Europe, the current no-needle injectors are already widely used by children who take a human growth hormone.
Although costly, the current needleless technology has been liberating for many patients. Robert Landerf, a La Pine (Ore.) businessman who injects insulin twice a day, says the device has helped him feel freer to travel to Fiji for skin diving, one of his new hobbies.By Pallavi Gogoi; Edited by Catherine ArnstReturn to top