• WordNet 3.6
    • n alumina any of various forms of aluminum oxide occurring naturally as corundum
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Webster's Revised Unabridged Dictionary
    • n Alumina (Chem) One of the earths, consisting of two parts of aluminium and three of oxygen, Al2O3.☞ It is the oxide of the metal aluminium, the base of aluminous salts, a constituent of a large part of the earthy siliceous minerals, as the feldspars, micas, scapolites, etc., and the characterizing ingredient of common clay, in which it exists as an impure silicate with water, resulting from the decomposition of other aluminous minerals. In its natural state, it is the mineral corundum.
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Century Dictionary and Cyclopedia
    • n alumina The oxid of aluminium, Al2O3, the most abundant of the earths. It is widely diffused over the globe in the shape of clay, loam, and other similar substances; corundum, in its varieties adamantine spar, the ruby, and sapphire, is alumina nearly pure and crystallized. In these forms alumina is, next to the diamond, the hardest substance known. Its great value in the arts depends on its affinity for vegetable coloring matters and animal fiber. It forms the base of the lakes in dyeing, and acts also as a mordant. United with silica it is extensively used in the manufacture of all kinds of pottery and porcelain-ware, crucibles, mortar, and cements.
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Chambers's Twentieth Century Dictionary
    • n Alumina al-ū′min-a one of the earths, the characteristic ingredient of common clay—the oxide of aluminium
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Webster's Revised Unabridged Dictionary
L. alumen, aluminis,. See Alum
Chambers's Twentieth Century Dictionary
L. alumen, alum.


In literature:

With one exception (alumina) all these bodies are important ingredients of agricultural plants.
"Peat and its Uses as Fertilizer and Fuel" by Samuel William Johnson
The felspars are composed of silica and alumina, along with potash, soda, and lime, with traces of iron and magnesia.
"Manures and the principles of manuring" by Charles Morton Aikman
Melilite, a lime-alumina-silicate, is characteristic of certain very basic rocks, the melilite-basalts.
"Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 3" by Various
It is composed of silica, alumina, carbonate of lime, magnesia and oxide of iron.
"Museum of Antiquity" by L. W. Yaggy
This was a silicate-alumina rock, not a nickel-iron one.
"Anything You Can Do" by Gordon Randall Garrett
Alumina is high in the finer clays (18 to 30%), and they are the most aluminous of all sediments, except bauxite.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 4" by Various
Carbonate of Magnesia 1.40 to 2.58 ,, Alumina and Oxide of Iron 6.00?
"Island Life" by Alfred Russel Wallace
It differs also according to the amount of alumina present in it.
"Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 3" by Various
In some instances, alumina, which is likewise deposited from the hot waters, is the mineralizing material.
"Principles of Geology" by Charles Lyell
The earliest known glazes (Egyptian and Assyrian) were silicates of soda and lime containing very little alumina and no lead.
"Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 6" by Various

In news:

Orbite Aluminae Inc recently announced it has broken ground on the conversion of its high-purity alumina (HPA) plant in Cap-Chat, in the Gaspé region of Quebec, Canada.
Morgan Technical Ceramics receives US trademark for Sharkskinâ„¢ high-roughness textured alumina .
The fuel oil contained 20-40 ppm of silica and alumina.
Has completed the sale of 50 percent of the Aluminum Oxide Stade GmbH alumina refinery in Stade , Germany.
Suriname Aluminum Co LLC (Suralco) recently announced that production at the Paranam, Suriname , alumina refinery was being curtailed by approximately 40%, or 870,000 metric tons per year (mtpy).
Teleportation takes place inside an ion trap made of gold electrodes deposited onto alumina.
Sharkskin provides a high-roughness surface texture integral to the alumina base material.
Approved engineering work for a planned expansion of its Pinjarra alumina refinery in Western Australia .
3,4 Glass-infiltrated ceramics consist of a product formed by infiltrating molten glass into a partially sintered oxide material (aluminous oxide or alumina- zirconia oxide).
Examples of this are InCeram Alumina and InCeram Zirconia (Vident).
There is a lot of interest today in joining engineered-ceramic materials (such as alumina) to themselves or to metals.
S.) for alumina, a key material in the production of aluminum, following the alleged bribes .
Alumina ceramics offer a high-strength, low-cost advantage over any other technical ceramic .
With a long service life, alumina fixtures are extremely cost effective solutions compared to other common braze fixtures .
Wesgo Duramic (MTC Wesgo Duramic) announces that it has published a new brochure on its precision-engineered brazing fixtures , which are ideal for high temperature alumina ceramic applications.

In science:

Indeed the cells were not identical: the material of the cell tube (alumina ceramics vs monocrystalline sapphire), the polishing/origin/tilt of the windows, the filling of the cells (unexpected foreign gas observed in cell #3) etc. were different.
Pump-probe measurement of atomic parity violation in caesium with a precision of 2.6%
Speaking on circular guide systems it would be important also to consider natural nanotube systems (carbon or carbon based nanotubes, alumina porous membranes) [40,41].
On X-Ray Waveguiding in Nanochannels: Channeling Formalism
Verhoelst et al. (2006) have made a combined analysis of the near and mid-infrared undispersed interferometric and spectroscopic data and showed in addition to H2O, OH and CO the likelihood of amorphous alumina in the MOLsphere, a dust species with a high sublimation temperature.
The molecular and dusty composition of Betelgeuse's inner circumstellar environment
The only dust species which can survive at these high temperatures and which provides significant opacity at these wavelengths is alumina (Al2O3 ).
The molecular and dusty composition of Betelgeuse's inner circumstellar environment
Optical depths observed with MIDI (black diamonds) and high-resolution opacity pro files of water (black), SiO ( grey) and alumina (solid grey line).
The molecular and dusty composition of Betelgeuse's inner circumstellar environment