Red Light, Green Light
Researchers at Philips and the University of Amsterdam in the Netherlands have created the first material for light-emitting diodes (LEDs) and flat-panel displays that can glow two different colors. Other electroluminescent materials, like the familiar LED indicators on VCRs, emit light of one fixed hue when electricity flows through them. As a result, multicolor devices, such as flat-screen televisions and computer monitors, have required three different materials-one each for red, green, and blue.
The new material is a mixture of a semiconducting polymer and a compound containing the metal ruthenium. Applying a voltage in one direction excites the metal, causing it to emit red light; an opposite voltage excites the polymer, which glows green. The dual-color material will allow designers to create full-color displays using two, rather than three, materials. This advance will simplify manufacture, and it will yield brighter displays because a larger portion of the screen surface will emit light at any given time. Philips expects the first small full-color displays that use the materials to be ready for market within three to five years.
Villagers in remote parts of India will soon be surfing the Web, thanks to a new Internet-on-wheels device. Built by researchers at the Indian Institute of Technology in Kanpur, India, in collaboration with MIT’s Media Lab Asia, Infothela consists of a covered tricycle with a steel platform that carries a computer linked to the Internet by a wireless antenna. A 12-volt battery tucked below the platform powers the computer: as the Infothela operator rides from village to village, offering Internet access at each stop, a pedal generator recharges the battery. Should the rider tire, the battery can be charged with electricity from an outlet or a diesel generator. The Indian researchers are working on ways to translate Internet content into local languages, and they are developing audio- and video-based software that would make the Net accessible to people who can’t read. Prashant Kumar, head of the project’s mechanical-design team, expects Infothela to begin its village-hopping voyage within the next three to five months.
Remember those red-and-green glasses that made some movies look 3-D? Now there’s an easy way to create similar effects on any printed matter-without glasses. A new color-rendering process from Xerox Research and Technology in Webster, NY, prints two images on a single piece of paper in such a way that each image shows up only under specific lighting-red versus blue light, say. The heart of the system is new software that allows precise control over the process. The user tells the program which wavelengths of light should reveal each image, and it translates that into instructions for a standard printer. The technology could make document authentication that uses hidden watermarks cheap and simple, as well as allow for popcorn boxes that display different images depending on the light from a movie screen. Xerox has filed for patents on the technology.
Doctors may soon be able to steer a catheter through blood vessels via remote control. Catheters-long, flexible tubes-are used for biopsies, drug delivery, and other crucial medical tasks. Manually maneuvering a catheter to its target requires a doctor to push and rotate the outside end while monitoring the progress via x-rays. The new navigation method, under development by radiologist Ronald Arenson at the University of California, San Francisco, uses magnetic technology. The catheter’s tip is encircled by copper coils. As the patient lies within a magnetic field, a doctor uses a joystick to control the flow of electrical current to the coils; the current causes the catheter to realign itself with respect to the field. Such fine control, says Arenson, “will allow us to get to parts of the brain and body that are not easily accessible right now.” Arenson says that it will be five to eight years before the system is approved for human use.
For years beauticians wielding handheld electrodes have used electricity to treat skin blemishes and to improve the absorption of creams and lotions. Now a thin disposable patch from PowerPaper in Einat, Israel, could let aesthetes do the same thing at home. The patch contains flexible, one-half-millimeter-thick 1.5-volt batteries that generate a weak current. The current travels to the skin via a printed electrode and an underlying layer of conductive gel. Used alone, say PowerPaper’s developers, the system massages the skin and stimulates blood flow. Used in combination with, say, an antiwrinkle cream, the current drives positively charged molecules from the cream onto the skin-a process called iontophoresis, which, according to PowerPaper, speeds results of cosmetic treatments. The company is conducting tests with partners in the cosmetics industry and plans to market the patch by the end of this year.
Environmental startup In-Pipe Technology has a cheap fix for today’s overloaded sewage-treatment plants: a potent brew of bacteria that can digest society’s effluent before it reaches the plant and can clean the sewer lines in the process. Bacteria are already critical sewage additives for treatment plants, but In-Pipe in Wheaton, IL, is the first to employ them under the streets. Released into sewer mains in a steady drip, In-Pipe’s concentrated blend of naturally occurring bacteria colonizes the pipe walls, displacing indigenous microbes that emit offensive sulfurous odors and corrode the pipes. In-Pipe president Daniel Williamson says the colonizers are also efficient eaters, cutting by 50 to 85 percent the biosolids that make it to the plant. Most of In-Pipe’s 14 installations are in southern states such as Florida, Mississippi, and Louisiana, where thanks to heat and humidity, sewer stench and corrosion are year-round nuisances. Armed with two years’ worth of performance data, Williamson is raising funds to bring In-Pipe’s relief to stinky sewers across the United States.
Because conventional computers work with one small chunk of data at a time, they’re lousy at distinguishing faces and other subtly varying patterns. An “associative memory” under development at Syracuse University may solve the problem by enlisting a protein found in salt marsh bacteria. When exposed to laser light, the protein, called bacteriorhodopsin, twists into various positions that change its color. A database of images-faces, for instance-could be written by lasers into a layer of the protein. To find a match for an unidentified face, its image could be projected simultaneously onto all the images stored in the database; the superimposed pair of images whose features match most closely will glow the most brightly. A lab version of the system can already distinguish printed letters, but a commercial prototype is at least five years off, says Syracuse team leader Jeff Stuart. The researchers are looking for ways to write higher-resolution images with smaller lasers.
Striking Lightning Out
Lightning fries more than $1 billion worth of sensitive computer, television, and stereo equipment each year; startup Storm Shelter Electronics in Savannah, GA, has developed the first commercial device that provides protection from these massive power surges. Storm Shelter continuously monitors data from the National Lightning Detection Network (a network of sensors operated by Vaisala in Tucson, AZ) and wirelessly pages a user’s device whenever lightning strikes within six kilometers. The device sounds an audible alert. Twenty seconds later, it disconnects the power to all linked electronics by creating an internal physical gap of two centimeters, across which an electrical surge as great as 34,000 volts cannot jump. (Standard surge protectors can handle spikes of only several hundred volts.) Once the threat has passed, Storm Shelter sends an all-clear page and reconnects the power. The company plans to start selling a commercial product in late spring; a consumer version is scheduled for next year.
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