CRYSTAL CRUCIBLES: @Ames high-quality crystals are essential to worldwide efforts to determine the properties of materials.
Ames Laboratory researchers produce such crystals in special crucibles like these which have been turned upside down to show their pointed bottoms. This design limits the number of possible site where a crystal can begin to grow.
When it comes to creating new materials, single crystals play an important role in presenting a clearer picture of a material’s intrinsic properties. A typical material will be comprised of lots of smaller crystals and the grain boundaries between these crystals can act as impediments, affecting properties such as electrical or thermal resistance.
An exception to this rule is that at high temperature, relative to the melting point, small crystals can have a tendency to slide past one another, a property called creep. It’s for this reason that turbine blades in some jet engines or generators are actually formed from single crystals of nickel-based alloy. A few other everyday applications using single crystals are semi-conductors, detectors, such as infrared or radiation sensors, and lasers.
From a research viewpoint, especially when creating a new material, scientists want to remove as many variables as possible to best understand a material’s properties.
One of the better known methods, the Bridgman technique uses a crucible with a pointed, conical end. This fine point promotes the growth of a single crystal as the crucible exits the heated portion of the furnace. Heat is provided through a heating element similar to the one in a home oven (resistance) or via a magnetic field (induction). _
Ames Laboratory also has a special Bridgman furnace that allows crystal growth at higher pressures. This allows growth of crystals from alloys that contain volatile components. The high pressure prevents these components, which have a lower boiling point than alloy’s other components, from flashing off as a vapor before the crystal can form.
"Arid City" What I fear the future may look like.
Paint sometimes seems to have a mind of their own. I was messing around in my sketchbook, as always, trying to use up some leftover paint and this just happened to be created. Arid is what came to mind immediately which led me to start thinking about what the future conditions of our planet Earth could look like. #city#hot#sketchbook#acrylicpainting#fire#future#arid#art