Section A Directions: In this section, there
is a short passage with 5 questions or incomplete statements. Read the passage
carefully. Then answer the questions or complete the statements in the fewest
possible words. Please write your answers on Answer Sheet
2.
Scientists have known for decades that coffee beans contain oil. Mohapatra
and colleagues, however, were the first to analyze coffee grounds.
Used grounds usually end up in landfills, though gardeners
sometimes use them as a kind of fertilizer. The scientists collected used
grounds from Starbucks, which gives bags of grounds away as part of the
company’s "Grounds for your garden" program. To prepare
the grounds for analysis, the team first dried them in an oven. They mixed the
resulting powder with a combination of solvents (溶剂) that caused the oil to
separate from the solution. They extracted the oil, saving the solvents for the
next round of processing. The remains could still be used as compost, ethanol
feedstock, and fuel pellets. "We’re not wasting
anything, " Mohapatra told Discovery News. "It’s a recycling process."
The study showed that used grounds contain about
15 percent oil by weight, depending on the type of coffee. That’s not too far
off the proportions in soybean, rapeseed, and palm oils, which are also used as
sources for bio-diesel. And coffee oil is more stable than these other sources
because of its high antioxidant content, found the study, which appeared in
December in the American Chemical Society’s Journal of Agricultural and Food
Chemistry. Around the world, growers produce more than
16 billion pounds of coffee each year, according to the U.S. Department of
Agriculture. The scientists estimate that spent grounds could add 340 million
gallons of bio-diesel to the global fuel supply.
Mohapatra pictures a streamlined coffee recycling system, in which the
same trucks that deliver beans to Starbucks could pick up the brewed waste and
head to a bio-diesel plant. The plant would be close by, to save on
transportation costs and emissions. Coffee grounds
appear to produce high-quality oil, granted Robert McCormick, an engineer at The
National Renewable Energy Laboratory in Golden, Colorado. But, he said, coffee
probably won’t be a practical solution to the world’s energy needs.
For one thing, the country’s main sources of bio-diesel-cooking oil
and animal fat-are 100 percent oil, compared to coffee’s 15 percent. And even
when a cafe brews a large amount of coffee, relatively few grounds are left
behind. It takes 50 gallons of spent grounds to produce just 1 gallon of oil,
Mohapatra said. Still, McCormick commends the
researchers for thinking outside the box about the world’s energy issues.
"Anything that takes a waste product and makes a fuel
out of it is really a positive," he said. "This is pretty cool. " With the "Grounds for your garden" program, Starbucks encourages people to use coffee grounds as______.