Information AboutVitrification |
| CATEGORIES ABOUT VITRIFICATION | |
| chemical processes | |
| cryobiology | |
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Vitrification is a process of converting a material into a Glass -like Amorphous Solid which is free from any Crystal line structure, either by the quick removal or addition of Heat , or by mixing with an additive. Solidification of a Vitreous solid occurs at the Glass Transition Temperature (which is lower than Melting Temperature , ''T''m, due to Supercooling ). When the starting material is solid, vitrification usually involves heating the substances to very high Temperature s. Many Ceramic s are produced in such a manner. Vitrification may also occur naturally when Lightning strikes Sand , where the extreme and immediate heat can create hollow, branching rootlike structures of glass, called Fulgurite . When applied to whiteware ceramics, vitreous means the material has an extremely low Permeability to liquids, often but not always water, when determined by a specified test regime. The microstructure of whiteware ceramics frequently contain both Amorphous and crystalline phases. EXAMPLES When Sucrose is cooled slowly it results in crystal Sugar (or Rock Candy ), but when cooled rapidly it can form syrupy Cotton Candy (candyfloss). Vitrification can also occur when starting with a liquid such as water, usually through very rapid cooling or the introduction of agents that suppress the formation of Ice crystals. This is in contrast to ordinary Freezing which results in ice crystal formation. Additives used in Cryobiology or produced naturally by organisms living in Polar Region s are called Cryoprotectant s. Arctic Frog s and some other Ectotherm s naturally produce Glycerol or Glucose in their Liver s to reduce ice formation. When glucose is used as a cryoprotectant by Arctic frogs, massive amounts of glucose are released at low temperature and a special form of Insulin allows for this extra glucose to enter the cells. When the frog rewarms during Spring , the extra glucose must be rapidly eliminated, but stored. Arctic Insect s also use sugars as cryoprotectants. Arctic fish use Antifreeze Protein s, sometimes appended with sugars, as cryoprotectants. APPLICATIONS Ordinary soda-lime Glass , used in windows and drinking containers, is created by the addition of Sodium Carbonate and lime ( Calcium Oxide ) to Silicon Dioxide . Without these additives silicon dioxide will (with slow cooling) form Sand or Quartz crystal, not glass. |
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