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In this issue:
Effect on SLAC of a Federal Shutdown
Accelerator Applications: Clean, Green Containers for Food and Drink
Word of the Week: Harmonic

SLAC Today

Friday - April 8, 2011

Effect on SLAC of a Federal Shutdown

If Congress does not take action before midnight tonight, there will be a government shutdown. A shutdown would not immediately affect SLAC operations. If there is a shutdown, the lab will continue operations until further notice.

Accelerator Applications: Clean, Green Containers for Food and Drink

(Photo - children eating lunch)
(Photo: Cindy Arnold, Fermilab.)

The U.S. Centers for Disease Control and Prevention estimate that 48 million people in the United States get sick each year and 3000 die from food-borne illness. A report published in 2010 by the Produce Safety Project estimates that food poisoning costs the US $152 billion a year.

Reducing this toll requires effective sterilization of food and beverage packaging. When choosing technologies to do this, industry is increasingly taking into account the environmental impacts.

A package must protect food quality as well as guard against contamination, so the compositions of both food and packaging material have to be taken into consideration when choosing a sterilization technology, says Susan Duncan, a scientist in the Food Science and Technology Department at Virginia Tech and spokesperson for the Institute of Food Technology. "These choices also have an environmental influence, and the industry is starting to have conversations about reducing its carbon footprint," she says.

Traditional methods for sterilizing empty packaging are simple and effective, but have environmental drawbacks. Steam and heat sterilization consume energy and water, and heat can damage materials. Sterilizing with chemicals such as hydrogen peroxide is energy efficient but can leave residues that seep into the food.

Low-energy electron beams from particle accelerators provide an environmentally friendly alternative.

"Electron beams are more efficient and chemical free," says Josh Epstein, the director of marketing at Advanced Electron Beams, a company based in Wilmington, Massachusetts that specializes in accelerator technology.

Read more in Symmetry magazine...

(Image: public domain, from Wikimedia Commons.)

Word of the Week: Harmonic

The word "harmonic" and its relations are usually associated with music, but harmonics can exist in all waves, not just sound waves generated by four-part harmony or wailing harmonicas. The wave traveling through a plucked string, the oscillations of a recoiling spring, electromagnetic waves—all can have harmonics.

A harmonic is essentially a second wave that is precisely half as long, or one-third as long, or one-quarter as long, and so on, compared to the original wave. For example, if the frequency of the first wave (how many times it oscillates each second) is 10 Hz, the frequencies of the harmonics are 20 Hz, 30 Hz, 40 Hz, and so on.

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