Sandia National Laboratories recently demonstrated that hollow organic nanotubes, married to an inorganic catalyst, can harness sunlight to turn water into pure hydrogen and oxygen. By 2006, Sandia researchers hope to have prototypes from which a new kind of solar cell could be made that would convert water into fuel. Such cells might replace fossil fuels in automobiles and thus reduce the United States' dependence on foreign oil. "If we get lucky and it works [efficiently], then we will try to engineer cells out of these things," said Sandia researcher John Shelnutt. "Then there is going to be a lot of work for EEs." Organic nanotubes are used throughout nature to transport electrons and to convert light into energy. In humans, for example, porphyrin nanotubes provide the power by which hemoglobin forms new proteins. The Sandia researchers believe they can harness the same mechanism to power automobiles with water.
Friday, March 25, 2005
Thursday, March 24, 2005
Virtual reality software has long held the promise of enabling designers to sculpt the sleek curves and contours of a new product from "virtual clay," but up until last year designers had to learn a whole new procedure for working with computer-aided design (CAD). Until now, virtual shapes could only be sculpted via keyboard and mouse input to define "splines" or similar mathematical objects that determine a curve's shape, but have nothing to do with sculpting. More recently, haptic feedback devices have arrived that offer a more direct relationship between the hand and a virtual object, but they still lack the naturalness of hand-shaped clay. A project of the State University of New York at Buffalo is seeking a direct intuitive method for working with virtual shapes in a CAD system using the type of glove developed in virtual reality systems. Using the approach, it is possible to work with actual clay to sculpt a shape, which is then automatically transferred to a CAD representation. "Ours is the only technology capable of transferring touch directly from the user's hand to the virtual object," said associate professor Thenkurussi Kesavadas, director of the Virtual Reality Lab
Posted by R. Colin Johnson at 3:10 PM
Monday, March 21, 2005
Critics of nanotechnology have fastened onto speculation by Sun Microsystems co-founder Bill Joy about runaway nanobots turning the planet into "gray goo," tainting the technology in all its forms. Now, cooperating engineering teams at the Georgia Institute of Technology and Rice University are angling to find out if that's so. Their preliminary results in measuring the behavior of nanomaterials in the environment show that the threats are real, but so is the hope of preventive solutions. A detailed study by the Georgia Tech and Rice researchers reveals that fullerene, one of the first nanomaterials, could threaten water supplies if not handled properly. In particular, nanoscale fullerenes were found to clump together in groundwater to form larger, micrometer-scale particles that could accumulate, gray-goo style. The researchers also found that saltwater broke up the clumps as well as various preparation steps that could be mandated by government regulators. "To look at a material's potential as a pollutant, how to minimize its environmental impact and make the industry sustainable is really the right thing to do," said John Fortner, a Georgia Tech research scientist and a Rice University doctoral candidate. Fortner performed the work with Joe Hughes, chairman of the Georgia Tech School of Civil and Environmental Engineering, under the auspices of the Rice University Center for Biological and Environmental Nanotechnology.
Wednesday, March 16, 2005
IBM Research (Yorktown Heights, N.Y.) announced in 2003 that it had invented carbon nanotube technology to enable the world's smallest solid-state emitter and the first electrically-controlled single-molecule light emitter. The light-emitting nanotube (LEN) operated in the important 1.5-micron range, portending optical communications on silicon chips with integrated 1.4-nm diameter LENs. "Our results show that nanotube-based light emitters can potentially be integrated with silicon electronic components, opening up new possibilities in electronics and optoelectronics," said Phaedon Avouris, manager of nanoscale science, IBM Research. IBM showed a detailed mathematical proof that is still relevant in 2005, along with verifying laboratory demonstrations of hitherto speculated properties of light emission by carbon nanotubes. In a nutshell, IBM discovered that simultaneous injection of electrons into one end, and holes into the other end, of a carbon nanotube causes it to emit light at the 1.5 micron wavelength.
Posted by R. Colin Johnson at 9:32 AM
Friday, March 11, 2005
An algorithm that simplifies the labor-intensive task of colorizing black-and-white motion pictures has been created at Hebrew University in Jerusalem. The algorithm lets simple scribbles accomplish what would otherwise demand exacting definition. "Our colorization algorithm does not require precise image segmentation or accurate region tracking," said Dani Lischinski, an assistant professor at the university's School of Computer Science and Engineering. Instead of precisely defining areas, as computer-generated techniques require, he said, the algorithm allows an artist simply scribble over areas with "crayons" of different colors. The algorithm then takes over, filling in the regions with the various colors and tracking them from frame to frame.
Posted by R. Colin Johnson at 8:44 AM
Thursday, March 10, 2005
A research group at the University of Delaware has demonstrated a way to precisely position and control the growth of organic nanowires atop a prepatterned substrate, potentially providing a means of interconnecting future nanocircuits. Until now, there has been no way to interconnect such nanoscale devices as carbon nanotube transistors, quantum dots and molecular-memory arrays. In a different approach, researchers at Purdue University have used the self-assembling properties of DNA to create nanowires. University of Delaware professor Thomas Beebe led the team that recently demonstrated nanowires that self-assembled in a thin-film polymer. By stimulating the fledgling wire at one end with a pulse from a scanning-tunneling microscope (STM), the wire self-assembled along the lines of the atomic lattice, yielding nanoscale precision. A barrier, called a corral, stopped the wires' growth at the correct point. This suggests that future devices could be interconnected using self-assembling nanowires that would be stimulated electrically to grow and then terminated with molecular corrals. Separately, researchers at Purdue University attached magnetic nanoparticles to DNA and then cut the strands into DNA wires. Deoxyribonucleic acid-DNA-has an overall negative charge, but when placed in a solution with magnetic particles that have a positive charge, DNA automatically self-assembles into tiny scaffolds that, in effect, create wires. Those wires can be used to self-assemble electronic devices according to a precise program.
Posted by R. Colin Johnson at 7:38 AM
Thursday, March 03, 2005
Using conventional materials-processing technology as a foundation, researchers at the University of California-Davis have developed nanotube-based thin films to build capacitors with a power density of 30 kilowatts per kilogram, a tenfold increase over previous devices. The "supercapacitors," with a scan rate of 1,000 millivolts/second, "can be manufactured very efficiently," according to their inventor, professor Ning Pan. Pan hopes to fabricate supercapacitors that can replace conventional batteries in handheld electronic devices. Two capacitor manufacturers are said to be competing to license the technology from UC Davis' Technology Transfer Center. "Supercapacitors built using electrodes made from our nanotube thin films exhibit very high power density, very high scan rates and nearly ideal cyclic voltammograms," said Pan, a professor of biological and agricultural engineering. "Also, our nanotube-based electrode material is simple and fast to prepare, since no binder is required." Researchers at the university's Nanomaterials in the Environment, Agriculture and Technology center, and consultant Jeff Yeh of Mytitek Inc. (Davis, Calif.), aided in the project. The company co-sponsored the research with the U.S. Missile Defense Agency.
Posted by R. Colin Johnson at 7:29 AM