UB engineers have created a more efficient way to catch rainbows, an advancement in photonics that could lead to technological breakthroughs in solar energy, stealth technology and other areas of research.
Qiaoqiang Gan, assistant professor of electrical engineering, and a team of graduate students described their work in a paper called “Rainbow Trapping in Hyperbolic Metamaterial Waveguide,” published Feb. 13 in the online journal Scientific Reports.
They developed a “hyperbolic metamaterial waveguide,” which is essentially an advanced microchip made of alternate ultra-thin films of metal and semiconductors and/or insulators. The waveguide halts and ultimately absorbs each frequency of light at slightly different places in a vertical direction to catch a “rainbow” of wavelengths.
Many industrial plants depend on water vapor condensing on metal plates: In power plants, the resulting water is then returned to a boiler to be vaporized again; in desalination plants, it yields a supply of clean water. The efficiency of such plants depends crucially on how easily droplets of water can form on these metal plates, or condensers, and how easily they fall away, leaving room for more droplets to form.
The key to improving the efficiency of such plants is to increase the condensers’ heat-transfer coefficient — a measure of how readily heat can be transferred away from those surfaces, explains Nenad Miljkovic, a doctoral student in mechanical engineering at MIT. As part of his thesis research, he and colleagues have done just that: designing, making and testing a coated surface with nanostructured patterns that greatly increase the heat-transfer coefficient.
WEST LAFAYETTE, Ind. - Technology developed by a food scientist at Purdue University could cook food that retains its "fried" flavor and consistency and has up to 50 percent less fat and fewer calories than food cooked using conventional methods.
The radiant fryer was developed by Kevin M. Keener, professor of food science in the College of Agriculture. It uses energy similar to sunlight to cook pre-formed food items like chicken patties, hamburgers and hash browns. Food is placed in wire trays that travel down a conveyor belt with radiant energy elements on either side.
Keener said many foods sold at fast-food restaurants are partially cooked at a factory and quickly frozen. Restaurant workers typically use an oil immersion fryer to finish the process.
Rice University scientists have unveiled a revolutionary new technology that uses nanoparticles to convert solar energy directly into steam. The new “solar steam” method from Rice’s Laboratory for Nanophotonics (LANP) is so effective it can even produce steam from icy cold water.
Details of the solar steam method were published online today in ACS Nano. The technology has an overall energy efficiency of 24 percent. Photovoltaic solar panels, by comparison, typically have an overall energy efficiency around 15 percent. However, the inventors of solar steam said they expect the first uses of the new technology will not be for electricity generation but rather for sanitation and water purification in developing countries.
A field of young sunflowers will slowly rotate from east to west during the course of a sunny day, each leaf seeking out as much sunlight as possible as the sun moves across the sky through an adaptation called heliotropism.
It's a clever bit of natural engineering that inspired imitation from a UW-Madison electrical and computer engineer, who has found a way to mimic the passive heliotropism seen in sunflowers for use in the next crop of solar power systems.
Unlike other "active" solar systems that track the sun's position with GPS and reposition panels with motors, electrical and computer engineering professor Hongrui Jiang's concept leverages the properties of unique materials in concert to create a passive method of re-orienting solar panels in the direction of the most direct sunlight.
His design, published Aug. 1 in Advanced Functional Materials and recently highlighted in Nature, employs a combination of liquid crystalline elastomer (LCE), which goes through a phase change and contracts in the presence of heat, with carbon nanotubes, which can absorb a wide range of light wavelengths.
A penny-sized rocket thruster may soon power the smallest satellites in space.
The device, designed by Paulo Lozano, an associate professor of aeronautics and astronautics at MIT, bears little resemblance to today’s bulky satellite engines, which are laden with valves, pipes and heavy propellant tanks. Instead, Lozano’s design is a flat, compact square — much like a computer chip — covered with 500 microscopic tips that, when stimulated with voltage, emit tiny beams of ions. Together, the array of spiky tips creates a small puff of charged particles that can help propel a shoebox-sized satellite forward.
Page 1 of 6