Quantcast

Latest Paulo Arratia Stories

2014-02-25 14:27:20

When deciding what materials to use in building something, determining how those materials respond to stress and strain is often the first task. A material’s macroscopic, or bulk, properties in this area — whether it can spring back into shape, for example — is generally the product of what is happening on a microscopic scale. When stress causes a material’s constituent molecules to rearrange in a way such that they can't go back to their original positions, it is known as “plastic...

2011-05-18 15:30:00

A biomechanical experiment conducted at the University of Pennsylvania School of Engineering and Applied Science has answered a long-standing theoretical question: Will microorganisms swim faster or slower in elastic fluids? For a prevalent type of swimming, undulation, the answer is "slower." Paulo Arratia, assistant professor of mechanical engineering and applied mechanics, along with student Xiaoning Shen, conducted the experiment. Their findings were published in the journal Physical...


Word of the Day
attercop
  • A spider.
  • Figuratively, a peevish, testy, ill-natured person.
'Attercop' comes from the Old English 'atorcoppe,' where 'atter' means 'poison, venom' and‎ 'cop' means 'spider.' 'Coppa' is a derivative of 'cop,' top, summit, round head, or 'copp,' cup, vessel, which refers to 'the supposed venomous properties of spiders,' says the OED. 'Copp' is still found in the word 'cobweb.'
Related