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July 5, 2010
Volume 88, Number 27
p. 80

Student Brewers, Radioactive Pool Cleaner, Smelly Helmets

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Northwestern University chemistry grad students Martin McCullagh and Jim Enterkin had at least two things in common when they met in Evanston, Ill., several years ago. Both enjoyed tasting different varieties of beer and had a desire to brew it themselves.

So McCullagh and Enterkin put their chemistry skills to use and started 
MAKING BEER in their kitchens in the winter of 2005. “The most expensive piece of equipment we have is a really big kettle,” McCullagh says.

What started with two students has grown to include nearly a dozen beer enthusiasts from Northwestern; all are graduate students in chemistry and other scientific fields. “I just realized there was a lot of interest,” says McCullagh, who is working toward a Ph.D. in theoretical chemistry. “So why not try to get together, motivate each other, and bounce ideas off each other?”

The group, formally named Northwestern Homebrewers Association (NHA), gathers every quarter for a tasting at one member’s house. The group designates a type of beer for each member to try their hand at brewing. This summer, the theme is “tropical,” and McCullagh and Enterkin have added pineapple to a German-style wheat beer.

Interestingly, none of the members of NHA is an organic chemist, and they all had to teach themselves the exact beer-making process, in which yeast essentially digest sugars and starches to make ethanol. “Having a chemical background helps greatly with the understanding of it,” says Enterkin, who lists beer brewing under the “Hobbies” section on his website. “There are lots of chemical processes going on.”

Radioactive algicide: Product cleans the pool and lights it up, all in one.

Newscripts reader and retired chemist James Francis, of Houston, recently came across an algae cleaner for swimming pools on the Internet. The problem is that the pool cleaner contains 95% carbon-14 as an active ingredient, according to the website parpool-spa.com. 14C is, of course, a RADIOACTIVE ISOTOPE.

Making assumptions about the amount of the active ingredient in aqueous solution, Francis estimates that a bottle of the algae cleaner should contain 31 g of 14C per L. Knowing that a curie—a unit of measured radioactivity—is 3.7×1010 decays per second, Francis estimates that a 1-L bottle would contain 187 curies of radioactivity. One curie is roughly equal to the radioactivity of 1 g of the isotope radium-226.

“Should be very effective,” notes Francis, who is also a member of the ACS Analytical Reagents Committee. “And besides, you wouldn’t need to turn on the pool lights at night.”

Cracked: A new bike helmet stinks out its owner when damaged.

Scientists at Fraunhofer Institute for Mechanics of Materials (IWM), in Freiburg, Germany, believe they have solved the problem of knowing when to retire a safety helmet: They have developed a new HELMET THAT SMELLS when it develops small wear-and-tear cracks.

Bicycle helmets do their job of protecting the head in a crash only if they are completely damage-free, according to IWM. Apparently, cyclists often replace helmets to be on the safe side, not knowing whether they have flaws.

The Fraunhofer researchers designed the injection-molded helmet to have microcapsules containing odoriferous oils enveloped by melamine formaldehyde resins. How it works is simple: “If cracks form, smelly substances are released,” according to IWM. “Large cracks really cause a stink.”

David Pittman wrote this week's column. Please send comments and suggestions to newscripts@acs.org.

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2011 American Chemical Society
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