The Cutting Edge: COMPUTING / TECHNOLOGY / INNOVATION : An Automatic Gear Shift for Bicycles
Unlike automobiles which come with either automatic or stick shift, bicycles require the rider to do all the shifting. This may be fine for most cyclists, but for Bruce Arden, a professor of engineering at the University of Rochester who commutes 15 miles a day by bike in stop and go traffic, the thought of a bicycle with “automatic” was intriguing. While there are a few automatic shifting bicycles on the market, they rely on complex mechanical systems that are often jerky and add extra weight.
Now a group of students at Arden’s university have put together a bicycle that uses a computer chip to find the right gear, no matter what the incline, or the cyclist’s energy level. Before setting off, the rider decides how fast he or she wants to pedal, and programs the information into the chip by pressing a few buttons. The chip “remembers” how fast the cyclist is supposed to pedal. When the rider begins to pedal faster, the bike automatically shifts to a lower gear.
The chip and shifting system run on two small 7.2-volt batteries. Along with the motor, the entire unit weighs between one and two pounds and would probably add about $200 to the cost of a bike. The main difference from a conventional bike, aside from the lack of a shift lever, is that when the cyclist stops the chain keeps turning so that the bike can continue to shift.
Mr. Sand Man: A 100-year-old water filtering technology, long since abandoned in favor of chlorine treatment, is making a comeback, in part due to the efforts of Robin Collins, a civil engineering professor at the University of New Hampshire. The technology is slow sand filtration, and its time may be coming again as concerns mount about the health effects of chemical purification.
When water is allowed to trickle through a layer of sand, it actually ends up drinkable by the time it exits out the bottom. That’s because a slimy layer of bacteria grows on the surface of the sand. As water trickles through, any disease-causing agents present are intercepted by the bacteria. So is decayed plant matter that causes water discoloration.
When the bacteria layer gets so dense it impedes water flow, the filtration pool is drained and the sand raked to restore its performance. Slow sand filtration plants are already in operation in Gorham, N.H., and Rutland, Vt.
Collins currently has a grant from the Thames Water utility in England and Calgon Carbon to figure out the best way to incorporate a layer of granular activated carbon in the sand. Adding carbon would increase the surface area of the sand, which in turn would provide more space for helpful bacteria to live. It will still be necessary to add some chlorine to protect the water’s quality as it flows through mains and pipes, but the sand filtration would dramatically reduce the quantity needed.
True Grit: Corn, that most versatile of crops, has been used for the last decade as a drying agent for the ethanol used in automotive fuel. Ethanol, produced from fermented corn, contains water in its initial form, and the water must come out before ethanol can go into your car’s gas tank. Today, about half of all the the ethanol produced is filtered with a corn grit process developed at Purdue University.
And now corn grits may also become part of so-called evaporative coolers, which are growing popular as replacements for ozone-depleting air conditioners. Known fondly in the West as the “swamp cooler,” evaporative coolers lower air temperature by passing warm air through a water spray or through wet, porous pads. That causes the air to become more humid, and thus in order to create the dry coolness most people expect from an air conditioner, manufacturers add water-absorbing particles.
Mike Ladisch, the Purdue agricultural scientist who developed the corn grit drying system for ethanol, says that grits look like a low-cost, natural substitute for the inorganic particles used in these new cooling systems. Just a few more tests are needed to work all the kinks.
An Angel in My Computer: Given the current enthusiasm for angels, it was only a matter of time before these heavenly messengers got introduced to the digital age. MIT researchers have come up with guardian angel (GA) software agents that would help track, manage and interpret a person’s health history.
Current health information systems yield fragmented patient records in which information is sometimes incorrect or inaccessible. The GA software will comb electronic medical records--and medically relevant legal and financial information--in order to maintain a comprehensive medical file, accessible in a timely manner as a person moves through life, work assignment, and health care providers.
