Technology Bulletin

Statellites, machine vision, radar to assist farmers

The day when farmers tap into computers, videos, and orbiting satellites to zap weeds and other pests isn't far off. Engineers at the University of California, Davis, have designed new chemical application technologies to help farmers deal with pests and have less impact on the environment, says David Hills, chairman of the UC Davis Department of Biological and Agricultural Engineering. Engineers recently demonstrated several systems, such as an automatic spray drift and rate-control system that uses flow-control valves on each spray nozzle and boom pressure-regulating valves to achieve independent flow rate and droplet size control. The system lets a farmer reduce spray drift in sensitive areas within seconds by adjusting a switch in the tractor cab, or by using automated satellite global positioning equipment. Likewise, a "smart" herbicide applicator delivers herbicides only to weed foliage, not the surrounding ground. The applicator combines machine vision with a radar-based speed detector to "see" target weeds, and adjusts a vertical boom of individually activated rapid-response spray nozzles. Jets of spray are directed only to identified weeds. For additional information, FAX the UC Davis Department of Biological and Agricultural Engineering at (916) 752-2640.

Process recovers steel and zinc from galvanized scrap

Engineers at Argonne National Laboratory (ANL), Argonne, IL, and Metal Recovery Industries Inc., East Chicago, IN, have developed technology for converting galvanized steel scrap from stamping-plant waste into clean scrap for steelmaking. Further development may allow the process to be used to de-zinc steel scrap from obsolete cars, say Argonne researchers. An electrochemical process dissolves the zinc coating from the galvanized steel surfaces. The zinc is then electroplated on a receiving electrode as a fine flake and recycled. Engineers have demonstrated the process in batch operations on about 1,000 tons of scrap; a pilot plant designed to continuously process about 36,000 tons of scrap each year is now operating in East Chicago, IN. Test runs at the plant will produce de-zinced scrap for iron- and steelmaking tests and recover zinc. The first commercial demonstration is expected next year. For more information, FAX ANL at (708) 252-5230.

Lasers cool this refrigerator

Under the right conditions, energy in the form of laser radiation can actually cool solid objects. Los Alamos National Laboratory researchers reported in an October issue of Nature magazine that "optical refrigeration" is not only possible, but efficient enough that it someday could provide reliable cooling for electronics in outer space and ultra-fast computer circuits. When light hits a solid object, it usually deposits energy as heat. But researchers recently demonstrated how light can be tuned to absorb energy from microscopic thermal vibrations in the solid and thus decrease the object's temperature. Using a tunable laser and modern fiber-optic materials, the Los Alamos researchers shined a beam of infrared light to cool a quarter-inch-long sliver of ultrapure glass impregnated with ions of the element ytterbium. The researchers' goal is to create what they call the "Los Alamos Solid-State Optical Refrigerator," or LASSOR, which would cool electronic devices to at least liquid-nitrogen temperature, and eventually lower. The LASSOR would use efficient, compact, high-powered diode lasers, have no moving parts, and weigh a couple of pounds. LASSORs might be ideal for space, where they could cool detectors and instruments mounted on satellites. More information can be found at at http://labs3.lanl.gov/cooling.asp.

Shock-wave studies prevent unwanted explosions

A large part of weapons safety is preventing unwanted detonation. Researchers need to accurately predict how the explosives inside a weapon might react when projectiles such as terrorist bullets violently penetrate the weapon. Now, with help from blue-green lasers, a special gas gun, and high-speed cameras, engineers at Los Alamos National Laboratory are measuring how a shock wave moves through explosive material to better understand the process. Data from the research, when coupled with explosive-modeling computer codes, will help insure that accidental detonations do not occur if a weapon is violently shocked. Researchers Blaine Asay, David Funk, and Gary Laabs have demonstrated the solution to a mechanical problem regarding the shape distortion and heat distribution of a physical compression wave that may produce detonation in high-explosive weapons. Because the shape of this wave determines how the explosive might release the energy of the entire weapon, the experimental data are key for verifying models for different accident scenarios. For details, FAX Asay at (505) 667-0500, or email bwa@lanl.gov.

ARPA, industry team to develop flat-panel displays

Silicon Video Corp. (SVC), San Jose, CA, will work with the U.S. Advanced Research Projects Agency (ARPA) to develop and manufacture thin cathode ray tube (CRT) flat-panel displays. The company has raised $95 million from government programs and partners, such as Hewlett-Packard and Compaq Computer, and plans to raise $400 million by 1998. The funds are slated for development of thin CRTs for both commercial and defense applications. In the commercial arena, flat-panel displays are now used for laptop computers and a growing number of consumer and communications devices. Defense uses range from miniature displays for head-mounted and weapons-sighting applications to larger devices for cockpit instrumentation and computer displays. "The soldier of tomorrow will be carrying some sort of portable computer and he will need state-of-the-art displays made in the U.S.," says Mike Sturiale, SVC director of marketing. The thin CRT design uses high-voltage cold-cathode technology and offers low power requirements for portable applications, say engineers. The design combines semiconductor and cathode ray tube manufacturing techniques and is expected to produce flat-panel displays that will be easier to manufacture, lighter weight, and consume less power than active matrix liquid crystal displays. For more information, FAX SVC at (408) 229-0664.

Face-recognition software may bolster security

If computers could recognize a face, they would be more useful in security applications, such as access control and fraud detection. To help computers do this, engineers at Miros Inc., Wellesley, MA, have developed new software that they say is able to recognize people's faces. Miros engineers claim to have solved a problem that has been plaguing face-recognition attempts: The difficulty of recognizing the same face reliably in spite of different expressions and minor changes such as haircuts. Miros' TrueFace 1.3 software runs on a desktop computer and compares the image from a camera attached to the computer to a stored database of faces at the rate of 200 faces per second, according to company president Michael Kuperstein. Such technology has been hampered in the past by small changes in a person's face. TrueFace concentrates on constant features rather than variables, such as the length of hair, expression, or orientation of the face, says Kuperstein. However, dark sunglasses do keep the system from recognizing a face, as will the addition or removal of a heavy, dark beard. One likely application would be controlling access to buildings or rooms, says Kuperstein. Potential users include immigration authorities, law enforcement agencies, and prisons. For details, FAX Miros at (617) 235-0720.

'Spying' on active atoms may help deter corrosion, boost microcircuits

If scientists could better understand how an atom travels at different temperatures and how it is incorporated into surfaces, they might be able to make smaller, faster, smarter electronic structures, such as microcircuits. Likewise, electrochemists could watch how corrosion occurs--one atom at a time. Now, physicist Brian Swartzentruber of Sandia National Laboratories can observe an atom in motion by programming the needle-like sensor of a scanning tunneling microscope (STM) to ride the atom's high point. Swartzentruber uses lateral electronic feedback from a surface's atomic topography to supplement the vertical feedback ordinarily provided by the microscope. The technique achieves a much faster imaging time interval than an STM by following a selected atom instead of the entire image field. Unlike previous methods, the technique works at elevated temperatures where some materials begin to be unstable--allowing researchers to observe corrosion and crystal growth. For details, FAX Neal Singer at (505) 844-1392.

Cleaner coal?

Scientists from Southern Illinois University have developed a process for cleaning coal that improves its quality and recovers 10% more of the energy-producing mineral than current methods. The research, funded by the Illinois Clean Coal Institute (ICCI), combines three commercially available technologies in a single integrated process to separate pyritic sulfur and other impurities from raw coal. The resulting coal produces less ash and sulfur by-products while yielding a higher energy output. The process begins with a hydrosizer which uses a stream of water to isolate and remove the heavier, coarse impurities. Next, the coal and fine-grain impurities travel to a mineral centrifuge for further separation based on weight. Finally, a flotation column uses a stream of air to separate the coal from the water. The system handles 30 times as much coal per hour as other coal cleaners and requires less floor space. For more information, FAX the ICCI at (618) 985-6166.

'Optical tweezers' let engineers tinker with cells

A biomedical engineer at the Johns Hopkins University is levitating particles within living cells, pulling on a cell's membranes, and tugging on protein molecules using light from a 10W Nd:YAG laser. The laser light allows researchers to have a pair of "tweezers" in a sterile container under a microscope. The optical tweezers, also known as a single-beam optical gradient force trap, operate via a joystick. Users can watch the magnified image of the microscope action on a video monitor screen. "The ability to go 'hands-on' inside a cell is something researchers have wanted for a very long time," explains Scot Kuo, assistant professor of biomedical engineering at Johns Hopkins. "Although I built my version of the microscope, they are available commercially, too." Kuo's studies of a molecular motor should shed light on how such motors work. For more information, FAX Johns Hopkins at (410) 955-4452, visit the World Wide Web site: http://infonet.welch.jhu.edu/news/news releases.