Since the early 1980s, 3-D printers have evolved from highly sophisticated lab (1) into affordable consumer items, enabling their owners to create their own increasingly complex designs.
Some futurologists see this as the beginning of the third industrial (2) , but environmentalists fear that the last thing the world needs is more nearly (3) plastic objects in landfills and oceans.
The main culprit is (4) petroleum-based plastic. There are environmentally friendly alternatives like polylactic acid plastic, or PLA, based on sugar from maize and (5) -- but they are more expensive.
Michiel Dusselier, a researcher at the University of Leuven, said scientists have found a way to (6) PLA faster and cheaper than before.
“Instead of a two-step process currently, it's a one-step process. Our process runs about 100 degrees centigrade lower in temperature and our (7) , which is kind of how much product can you make per volume of reactor per hour, are much higher and our product is also much cleaner, so we don't make side products,” said Dusselier.
PLA is one of the few types of plastic (8) not only for 3-D printers but for some biodegradable medical items such as suture threads.
“I think there will now be much more players in the market giving you the product at much lower prices and I think this will maybe really be the start of the PLA into the bio-plastic business,” said Bert Sels, a professor at the University of Leuven.
Although PLA is not suitable for all (9) , a petrochemical company is already developing the new process for mass production, raising hopes that more plastic products will soon be made of biodegradable (10) .
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上期答案
1. consequence
2. carnivores
3. poses
4. interactions
5. leopards
6. sanctuaries
7. gauge
8. populated
9. compensated
10. alternative