Biomedical Engineering Reference
In-Depth Information
1
The Unique Nature of Glass
Alexis G. Clare
Kazuo Inamori School of Engineering, New York State College of
Ceramics, Alfred University, Alfred, USA
1.1 WHAT IS GLASS?
We tend to think of glass as a single material fromwhich we manufacture
many useful articles, such as windows, drinking vessels, and storage
containers that can contain quite corrosive liquids, including aggressive
laboratory chemicals. Therefore, the glass has to be quite corrosion-
resistant and inert, including being able to maintain its optical properties
while being in aggressive environments such as a dishwasher or extreme
weather. For a material that we generally view as ''delicate,'' in terms of
attack from chemicals, it can be quite resistant. Another extreme envi-
ronment is the human body. An implanted medical device is subjected
to a warm and wet environment with continual fluid flow and com-
plex mechanical loads, but perhaps more importantly there are many
cells, some at work to reject foreign inert materials. They do this by
encapsulating the materials with fibrous (scar) tissue. Hip replacements
generally last 15 years or so, and in 2009 there was the story of a man
who cut himself shaving and out of his chin fell a piece of glass. He had
a lump under his chin, but he thought it was an abscess. In fact, 20 years
