Read the passage carefully and answer question.
The eco-friendly glass that’s hard to crack
There's laughter over the phone as John Mauro calls out my question to one of his researchers: just how much pummelling with a mallet does it take to break the new glass they have developed? "You've got to put your body into it," says Prof Mauro, of Pennsylvania State University, as he describes how the glass must first be scratched deeply with diamond or tungsten carbide stylus - and then hammered by a post-doctoral researcher wielding a mallet.
Prof Mauro claims the invention, called LionGlass, is ten times stronger than standard glass. Imagine a wine bottle unscathed, even after falling onto a tiled kitchen floor.
However, few details about LionGlass are available as the research has not been published in a peer-reviewed journal yet and the team have only recently filed a patent application.
One key detail is that, unlike standard glass, the production of this glass doesn't need soda ash or limestone. The alternative ingredients are currently a closely guarded secret.
Available: https://www.bbc.com/news/business-66359047. Accessed on Oct. 24th, 2023 [Adapted]
In "A post-doctorate researcher wielding a mallet", what does the underlined verb mean?
