Vitrification

Source: Wikipedia, the free encyclopedia.

Vitrification (from

ceramics, vitrification is responsible for their impermeability to water.[3]

Vitrification is usually achieved by heating materials until they liquidize, then cooling the liquid, often rapidly, so that it passes through the glass transition to form a glassy solid. Certain chemical reactions also result in glasses.

In terms of

molecules, forming blocks) becomes higher than a certain threshold value.[4] Thermal fluctuations break the bonds; therefore, the lower the temperature
, the higher the degree of connectivity. Because of that, amorphous materials have a characteristic threshold temperature termed glass transition temperature (Tg): below Tg amorphous materials are glassy whereas above Tg they are molten.

The most common applications are in the making of pottery, glass, and some types of food, but there are many others, such as the vitrification of an antifreeze-like liquid in cryopreservation.

In a different sense of the word, the embedding of material inside a glassy matrix is also called vitrification. An important application is the vitrification of radioactive waste to obtain a substance that is thought to be safer and more stable for disposal.

One study suggests[5][6][7][8] during the eruption of Mount Vesuvius in 79 AD, a victim's brain was vitrified by the extreme heat of the volcanic ash; however, this has been strenuously disputed.[9]

Ceramics

Vitrification is the progressive partial fusion of a

ASTM, who state "The term vitreous generally signifies less than 0.5% absorption, except for floor and wall tile and low-voltage electrical insulators, which are considered vitreous up to 3% water absorption."[14]

Pottery can be made impermeable to water by glazing or by vitrification. Porcelain, bone china, and sanitaryware are examples of vitrified pottery, and are impermeable even without glaze. Stoneware may be vitrified or semi-vitrified; the latter type would not be impermeable without glaze.[15][3][16]

Applications

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 in a liquid such as water, usually through very rapid cooling or the introduction of agents that suppress the formation of

cryo-electron microscopy to cool samples so quickly that they can be imaged with an electron microscope without damage.[17][18] In 2017, the Nobel prize for chemistry was awarded for the development of this technology, which can be used to image objects such as proteins or virus particles.[19]

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 would require very high temperature to obtain a melt, and subsequently (with slow cooling) a glass.

Vitrification is used in disposal and long-term storage of

Pacific Northwest National Labs, "Vitrification locks dangerous materials into a stable glass form that will last for thousands of years."[21]

Vitrification in cryopreservation

Vitrification in cryopreservation is used to preserve, for example, human egg cells (oocytes) (in oocyte cryopreservation) and embryos (in embryo cryopreservation
). It prevents ice crystal formation and is a very fast process: -23,000°C/min.

Currently, vitrification techniques have only been applied to brains (

neurovitrification) by Alcor and to the upper body by the Cryonics Institute
, but research is in progress by both organizations to apply vitrification to the whole body.

Many

woody plants living in polar regions naturally vitrify their cells to survive the cold. Some can survive immersion in liquid nitrogen and liquid helium.[22] Vitrification can also be used to preserve endangered plant species and their seeds. For example, recalcitrant seeds are considered hard to preserve. Plant vitrification solution (PVS), one of application of vitrification, has successfully preserved Nymphaea caerulea seeds.[23]

Additives used in

polar regions are called cryoprotectants
.

Tg (Glass transition temperature ) of sugars and plant vitrification solutions.[23]
Formula Tg (Mid, °C)
1M sucrose -30.9
1M glucose -41.3
1M trehalose -68.0
50% sucrose + 50% glycerol (PVS3) -90.7
50% sucrose + 50% EG -101.1
50% sucrose + 50% PG -89.1
75% sucrose + 25% glycerol -81.2
75% sucrose + 25% EG -80.7
75% sucrose + 25% PG -63.6
25% sucrose + 75% glycerol -91.3
25% sucrose + 75% EG -108.9
25% sucrose + 75% PG -98.0

See also

Literature

  • Steven Ashle (June 2002). "Divide and Vitrify" (PDF).
    doi:10.1038/scientificamerican0602-17
    . Retrieved May 10, 2015.
  • Stefan Lovgren, "Corpses Frozen for Future Rebirth by Arizona Company", March 2005,
    National Geographic

References

  1. ^ Varshneya, A. K. (2006). Fundamentals of Inorganic Glasses. Sheffield: Society of Glass Technology.
  2. OCLC 1228229824
    .
  3. ^
    ISBN 0901716561
    .
  4. doi:10.1016/j.jnoncrysol.2010.05.012
    .
  5. PMID 31971686
    .
  6. PMID 31971686
    . Retrieved 13 September 2020.
  7. ^ Pinkowski, Jennifer (23 January 2020). "Brains Turned to Glass? Suffocated in Boathouses? Vesuvius Victims Get New Look". The New York Times. Retrieved 2020-09-13.
  8. ^ "Mount Vesuvius eruption: Extreme heat 'turned man's brain to glass'". BBC News. BBC. 23 January 2020. Retrieved 2020-01-24.
  9. doi:10.1080/20548923.2020.1815398
    .
  10. ^ 'Role Of Accessory Minerals On The Vitrification Of Whiteware Compositions.' N.M.Ghoneim; E.H.Sallam; D.M. Ebrahim. Ceram.Int. 16. No.1. 1990.
  11. ^ Whitewares: Production, Testing and Quality Control. William Ryan & Charles Radford. Institute of Materials, 1997
  12. ^ 'Methods Of Extending The Narrow Vitrification Range Of Clays.' E.V. Glass & Ceramics 36, (8), 450, 1979.
  13. ^ 'Control Of Optimum Vitrification In Vitreous And Porcelain Bodies.' E.Signorini. Ceram.Inf. 26. No.301. 1991
  14. ^ ASTM C242-01. 'Standard Terminology Of Ceramic Whitewares and Related Products'.
  15. ^ 'Body Builders.' J.Ahmed. Asian Ceramics. June 2014 [full citation needed]
  16. ^ 'An Introduction To The Technology Of Pottery.' Paul Rado, Institute of Ceramics. 1988.
  17. doi:10.1111/j.1365-2818.1981.tb02483.x
    .
  18. S2CID 30869924
    .
  19. ^ "Nobel Prize in Chemistry Awarded for Cryo-Electron Microscopy". The New York Times. October 4, 2017. Retrieved 4 October 2017.
  20. doi:10.1007/s11661-010-0525-7
    .
  21. ^ "Waste Form Release Calculations for the 2005 Integrated Disposal Facility Performance Assessment" (PDF). PNNL-15198. Pacific Northwest National Laboratory. July 2005. Retrieved 2006-11-08.
  22. PMID 26539202
    .
  23. ^
    OCLC 1009363362.{{cite book}}: CS1 maint: date and year (link
    )
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