Researchers may have hit upon the holy grail of toxic-waste management: a system that runs on water and can detoxify just about anything.
There is a catch, of course.
The water used in the process has to be kept under high pressure at temperatures hotter than steam. This unusual and poorly understood state of water, called supercritical water, holds promise and problems for chemists, according to a report in Chemical & Engineering News.
The problem with supercritical water is that it is highly corrosive and so requires expensive corrosive-resistant materials to build reactors that use supercritical water to detoxify wastes.
Supercritical water has been used by Modec Corp. in Natick, Mass., to convert municipal-sewage sludge and pulp-mill waste into relatively harmless by-products. Also, the U.S. Defense Department is negotiating a pilot plant to use supercritical water to destroy military toxic wastes such as explosives and chemical agents.
In a supercritical state, when distinctions between liquid and gases disappear, water provides an excellent agent for oxidation of many chemicals found in toxic waste, scientists have found.
COMPUTER CONTROLS CONFUSE PILOTS Computer screens are replacing old-fashioned dials and switches in modern airplanes, but many pilots are used to those dials and switches and may be easily confused by computerized systems, researchers at Ohio State University report.
David Woods and Nadine Sarter questioned 135 airline pilots who are experienced at using computerized controls. They found that even among this experienced group, two-thirds expressed surprise at some of the things the system did in some situations. Almost half said they still don`t understand all the modes and features of their computer-control systems.
The problem, Woods said, is that the computers aren`t easy for pilots to use. They provide so much information on a screen that pilots often find they spend more time sifting through the computer routine than paying attention to flying the plane.
”This problem is an important one to solve,” Woods said, ”because human error remains the main culprit in airplane accidents.”
STRAWS CUT DAMAGE TO TEETH FROM POP Don`t savor soft drinks the way connoisseurs sample wine, dental researchers advise. It`s bad for your teeth to hold sugary drinks in your mouth and better to suck them up through a straw, advises the Academy of General Dentistry.
South African researchers confirmed that drinking with straws significantly reduces the amount of damage to teeth done by acid and sugar in soft drinks.
DATE-STAMPED APPLES MAY BE COMING SOON Fruits and vegetables may some day carry expiration dates much like those on cartons of milk or bottles of vitamins.
Researchers at Purdue University have found a way to use magnetic fields to determine sucrose levels in fruit; from that it`s possible to calculate ripeness and determine when the produce will become overripe.
The technology will be tested this year in some Indiana grocery stores.
POLLUTION OFFSETS OZONE DEPLETION Even though the Earth`s ozone layer is diminishing, harmful ultraviolet radiation isn`t getting through to the planet`s surface in a uniform fashion, scientists find.
The amount of ultraviolet radiation reaching industrialized urban areas actually appears to be falling, perhaps because it is dispersed by air pollution.
In a report in the December Geophysical Research Letters, scientists suggest that sulfate aerosols formed from industrial sulfur dioxide emissions are scattering incoming solar radiation in the atmosphere and reducing the actual amount of biologically active ultraviolet radiation that reaches the Earth`s surface.
