ne rib to the next using the oxygen molecules as stepping stones. Harrup, Stewart, and Luther are optimistic their battery design will ulti- mately change the battery industry. The team projects that its polymer mem- brane will be SO efficient at preventing battery run down, that batteries could sit unused for up to 500 months between charges with no loss of charge. Because the membrane is a flexible solid, it can be molded into any shape, which could open up new applications for batteries. The membrane is also very temperature tolerant, which could potentially solve portable power need prob- lems in the frigid cold of space. The team is already working with several federal agencies on applications for its lithium battery designs. 8.3 FUEL CELLS Although PC vendors are eager to breathe new life into their aging systems, particularly modestly equipped notebooks, at least one highly anticipated technology may not make it into the mainstream as soon as many vendors would like. Micro fuel cell technology has been aggressively touted as a convenient and easily renewable power source. The devices, which generate electricity through a chemical reaction between oxygen and a fuel such as hydrogen or methanol, can power a notebook for up to 40 hours. Yet, it's unlikely that large numbers of users will be "filling up" notebook PCs, PDAs, and other mobile devices anytime soon. Roadblocks for use include fuel cell size, the lack of a univer- sal standard, customer education issues, and safety and security concerns as users bring devices containing volatile fluids into buildings and onto airplanes and other vehicles. MICROCOMBUSTION BATTERY All of these drawbacks have made many notebook vendors skeptical about fuel cell technology. "Fuel cells are not likely to be relevant for mainstream mobile devices for several years," says Jay Parker, notebook products director for Round Rock, Texas-based Dell Computer. He believes it will be hard to change notebook users' ingrained habits. "Customers will need to become acclimated to refu