The Finest Atomizer, Bar None
Before long, you may find inkjets under the hood of your car or inside the engine of a fighter jet serving as exquisitely controlled fuel injectors. A conventional injector atomizes gasoline or diesel into tiny droplets, much the way a bottle of Windex sprays out a mist of fluid. The more completely the droplets vaporize and mix with air, the more efficiently the hydrocarbons burn. The inkjet (being the inkjet) is best equipped for the job. Researchers at Hewlett-Packard aren´t divulging details, but they say that they´re figuring out how to replace single-injector systems with hundreds of tiny inkjet nozzles, each with its own actuator, as a way to create even tinier drops for increased fuel efficiency.
Microscopic inkjet-based fuel-injection systems are already an indispensable component of the U.S. Navy´s experimental pulse detonation engine (PDE), which is designed to harness the energy of a violent fuel explosion and power a jet aircraft to Mach 3. The detonation depends on atomized droplets of fuel just 50 microns in width, which is why Jim Nabity, a senior researcher at TDA Research, turned to the inkjet nozzle. Its microscopic fuel dots vaporize so fast that they ignite, generating a thrust per pound of fuel comparable to any other supersonic engine, Nabity says.
the inkjet is great at micromanaging the small stuff, but with a few steroidal
modifications, it can work wonders on a macroscale too. Engineer Behrokh Khoshnevis of the University of Southern California is experimenting with oversize inkjet printers that, with the press of a button, can build custom housing from electronic blueprints. The automated system, which Khoshnevis calls Contour Crafting, consists of an overhanging carriage on which a nozzle slides back and forth, streaming layers of quick-setting concrete into walls [illustration, right]. â€It´s much like printing on paper,â€ the engineer says of his $30,000 brainchild. â€But unlike an inkjet print head that just moves sideways, our nozzle can move in all directions, like old vector plotters.â€ He is partnering with architects, construction companies and real-estate specialists to create a Contour Crafting center at U.S.C., and he predicts that the system will soon erect a 2,000-square-foot home in a single day, including the roof and conduits for plumbing and electricity. Later this year he plans to demonstrate a prototype capable of putting up 500-square-foot emergency shelters.
Three years from now, when you unroll your e-newspaper from its pencil-case-size tote for the latest headlines or show off your vacation snapshots on a 17-inch high-definition screen that folds up like a yoga mat, you can thank, yes, the inkjet. Dozens of companies worldwide are in a sprint to commercialize the technology of flexible plastic screens. Philips, for instance, is using a four-headed industrial-size inkjet with 256 piezoelectric nozzles to print organic light-emitting diodes-materials that glow when a current is applied-onto computer and television screens.
HP engineers in Bristol, England, are using inkjets to print tiny liquid-crystal dots onto a plastic substrate, where they serve as pixels. Electrodes in the bendable plastic turn the crystals on and off for a full-color display that could finally rival the printed page in resolution. Plastic Logic in Cambridge, England, hopes to release
Taking Drugs, the Smart Way
Conventional inhalers tend to spray a sloppy mist of large, uneven drops, and that´s fine for applications like asthma medications, which simply need to be dumped into the lungs. But it´s less than ideal for delivering most other drugs, which need to make it into the bloodstream. That could change when digital aerosols-thermal print heads inside inhalers that squirt tiny, perfectly uniform droplets-hit the market late this year. The aerosol, being developed by the Australian company InJet Digital Aerosols and being licensed to Canon, looks like a battery-powered inhaler. It delivers a mist of droplets between two and 20 microns in diameter, small enough to be absorbed through the lungs and in some cases directly into the bloodstream. InJet expects its inhaler to deliver drugs faster than pills or patches and with less pain than needles. Clinical trials are under way to test nicotine-filled inhalers as smoking-cessation devices.