Sounds influence sight
Designers of warning systems and human-machine interfaces should see what John P. McDonald has to say and hear him out. MacDonald is a University of California (San Diego) professor of neuroscience who is conducting studies on the connection between sight and sound. His work, which focuses on how people process sight and sound, has shown that attention drawn to a sound enhances an individual's ability to see. "Orienting attention to the location of a sudden sound primes the observer's visual system to process visual events that appear at the same location," he explains. His studies involved volunteers that had to identify whether a dim light appeared soon after a sound was presented. The sound and light appeared either on the same side or opposite side of the person's line of sight. MacDonald found that light was detected more accurately when it appeared on the same side as the sound. "Although we want to have a measure of the participant's perceptual sensitivity, we also want to deal with their decision processes," says MacDonald. "Some participants behave very conservatively in that they indicate they see the target light only when they are very sure that it was present. Other participants respond to just about everything," he says. He mentions that researchers know that the brain integrates information received from multiple stimuli in the environment and often ignores nonessential information, but also indicates that what we don't understand are the processes that enable us to selectively pay attention to events occurring in different modalities. In addition to improvements of warning systems and human- machine interfaces, the research also is relevant to design of radar operation systems. "We are now using measures of the brain electricity for determining whether orienting attention to a sound influences neural processing in visual parts of the brain," says MacDonald. "We are also investigating whether orienting attention to a sudden light influences the way we hear," he says. Future research will include studies of normal brain function involving different senses, and comparisons to individuals with abnormal brain function. For more information, write to the UCSD School of Medicine, 200 West Arbor Dr., San Diego, CA 92103 or call (858) 534-3797.
Micro-displays on Silicon
eMagin Corp. unveiled the world's first organic light-emitting diode (OLED) on silicon for use in entertainment, wireless, and computer microdisplays. The display technology is a derivative of Kodak's work on OLEDs. It uses a quad-pixel arrangement (four sub-pixels per color group) and crams 1.3 million micron-sized pixels into an area the size of a postage stamp. "Because our pixels are so much smaller than most others, we had to develop a method of making small color pixels different from the way other companies did it,' says Susan Jones, co-founder and executive vice-president of eMagin. Color filters built directly on top of the OLED display incorporate eMagin's high-speed white-light OLED technology and 1280-×1042-pixel IC array for real-time, full-color displays. OLEDs are emissive devices. They create light, unlike liquid crystal displays that require a separate light source. "Kodak and most other developers have built OLEDs that emit light downward through a transparent substrate of glass or plastic," says Jones. "We had to adapt the technology to emit light upward since our substrate is opaque," she says. The new OLEDs operate between 2 and 30V, depending on the design requirements. They have a wide viewing area—160 degrees—which is unlike other displays that fade when the viewer moves to either side of the display. Computer and video electronic system functions can be built directly onto the silicon under the OLED. Virtual Vision Inc., a subsidiary of eMagin, is developing miniature video and stereo sound RF transmitters and receivers for video and data headsets. RF transmission to headsets enables users to receive video from tabletop DVD players, cable, and other remote sources, without wires. The microviewer modules have lenses and electronic interfaces for integration into consumer and other original equipment applications. For more information, contact Jones at email@example.com or call (845) 892-1900.
'SnakeBot' inches along
Engineers at NASA's Ames Research Center are developing a snake-like robot called the "SnakeBot" that could one day explore other worlds. Why build a robot resembling a snake? Because snakes can slither through cracks, flip themselves backward over obstacles, coil, sidewind, and inch themselves along rough terrain. "A SnakeBot could navigate over terrain where a wheeled robotic rover would likely get stuck or topple," says Gary Haith, a lead SnakeBot engineer at Ames Research Center. The snake is a series of modules that hinge together in a chain. It has a wire that carries communications and power to and from the computer brain. NASA engineers are thinking about software that enables the SnakeBot to learn from its experience and remember how to navigate over rough terrain. SnakeBots are also attractive to NASA because they minimize spacecraft weight. The snake-like design enables the robot to perform tasks—like crawling off a spacecraft lander—without needing extra equipment such as a ramp. The snake's moving parts will be sealed inside a snake-like skin, protecting them from the outside environment. Haith also says that it is possible to include extra SnakeBot modules, in case repairs are needed. For more information, go to http://ic-www.arc.nasa.gov/ic/snakebot/ .
efficiently heats water
Heating the water we use in our homes for washing dishes, taking showers, and other tasks requires about 17% of the energy consumed by a typical household according to Oak Ridge National Lab (ORNL) statistics (Oak Ridge, TN). The lab helped develop a heat pump water heater that is more efficient than the conventional 50- and 80-gallon electric water heater it is designed to replace. Conventional tank-type water heaters are resistively heated, using heating elements located at the top and bottom of the tank. But even the most efficient electric water heaters achieve an energy factor of only 0.95 as electric energy is converted to heat energy. Energy Factor is a number closely related to the overall efficiency of a water heater, and is measured under controlled laboratory conditions and according to a standard laboratory procedure. On the other hand, the new heat pump water heater has an energy factor of 2.47, meaning that for every kWh of electricity the new heat pump uses for water heating, it produces the heat equivalent of 2.47 kWh of hot water. The heat pump is able to achieve such a high energy factor by extracting heat from the surrounding air.
"Most of the heat added to the water is taken from the surrounding air," says John Tomlinson, the senior development engineer at ORNL on the project. Tomlinson says that in a mature market the pump water heater's performance should provide a two-year payback. The current version of the heat pump water heater also cools and dehumidifies the surrounding air; however, a condensate-free version is in the making. The product is being commercialized by Enviromaster International (Rome, NY) and is expected to be released to the public in late 2001 or early 2002. "A key advantage of the new design is that it is installed just like a conventional electric resistance water heater and can be located in most places where conventional water heaters are installed," says Tomlinson. For more information, contact Tomlinson at firstname.lastname@example.org , call (865) 574-0291, or fax (865) 574-9329.
generates UV light
Researchers at Sandia National Labs have successfully demonstrated the first solid-state microcavity laser capable of producing ultraviolet light. The VCSELS (vertical-cavity surface-emitting lasers) are coated with phosphors, which generate the white light. White light is prized for lighting applications in a variety of commercial, consumer, and industrial applications. Currently, white light used for indoor lighting applications is provided by gas-filled fluorescent tubes used in offices, schools, and factories, or by incandescent bulbs used in most homes. The VCSELS work similarly to fluorescent tubes. Inert gases in fluorescent tubes emit ultraviolet light as electric current flows through them. The light rays strike phosphors that coat the tubes' inside walls, which causes them to emit visible light. VCSELS are made from thin layers of semiconductor materials that emit photons when electric current passes though them. The VCSELs use indium, which makes use of approximately 20% of the input power. Gallium nitride and aluminum nitride use only about 1% of input power, which is far less efficient than indium. For more information, go to www.sandia.gov .