Monday, July 28, 2008

New microwave oven material heats faster, saves energy

Inventors of a new material to be used in microwaves say it heats food and beverages more quickly and saves energy.

A microwave oven bombards food with microwaves, which are absorbed by certain molecules, including water, fats and sugars. The microwaves, powerful enough to kill viruses and bacteria, vibrate those molecules, heating the food.

"Conventional coffee cups are made from ceramic compositions which do not absorb microwaves and hence they do not heat up," explained Sridhar Komarneni, a professor of clay mineralogy at Pennsylvania State University. "When conventional ceramics are used for heating food, only food heats up and then the hot food heats up the ceramic."

Komarneni and colleagues in Japan made plates from a mix of 20 percent magnetite and 80 percent of a naturally occurring petalite mineral containing lithium, aluminum and silicon oxides. The new ceramic interacts with the microwaves and heats up, and "the microwaves heat up the container and hence the food," Komarneni told LiveScience. "Rice cooks in about half or less time."

And food stays hot longer.

"These ceramic materials not only heat up with microwaves but also retain heat for about 15 minutes and hence the food stays hot in the container," Komarneni said. "Ceramic plates could be used for pizza delivery as these plates are insulating materials."

A rice cooker and plates made from the material are already being sold by ASAHI Ceramics Research Co. in Japan.

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