The same radio waves that transmit Top 40 songs to billions of AM/FM radios could also make decontaminating wood more eco-friendly, according to a professor from the University of British Columbia.
The same radio waves that transmit Top 40 songs to billions of AM/FM radios could also make decontaminating wood more eco-friendly, according to a professor from the University of British Columbia.
Since the devastating spread of Dutch elm disease in the early 20th century, wood exporters have had to be careful about treating their products to prevent the spread of other diseases or invasive insects. The most popular methods are chemical baths in methyl bromide, which can have a negative environmental impact, and heat treatment, which can take more than a day, requires lots of energy, and can cause the wood to become too dry and crack.
However, Stavros Avramidis, a professor of wood science at the University of British Columbia, is using radio waves to decontaminate even large logs in only two to three hours without drying them out.
For years, Avramidis used dielectric heating to dry wood. This is the same process a microwave oven uses to heat food: Electric waves move through a material at a speed that causes water molecules in the material to vibrate and rotate, and that molecular commotion with the help of friction result in significant heat generation. Unfortunately, microwaves waves are too small to penetrate dense material like wood, so Avramidis turned to radio waves.
"The biggest challenge is designing the technology for the process. With radio waves you have to continuously 'tune' the frequency and energy of the waves, just like you would adjust an AM radio as you drive through a mountain range," Avramidis said in the article.
In April the Food and Agriculture Organization (FAO) of the United Nations approved the use of Avramidis's radio frequency pasteurization for use on pallets of processed and dried wood. Looking to the future, Avramidis hopes the FAO will approve the process for green wood and that large forest companies will test the process on a commercial scale.