• WordNet 3.6
    • n uranium a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons
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Webster's Revised Unabridged Dictionary
  • Interesting fact: Over 436,000 U.S. Troops were exposed to depleted uranium during the first Gulf war
    • n Uranium (Chem) An element of the chromium group, found in certain rare minerals, as pitchblende, uranite, etc., and reduced as a heavy, hard, nickel-white metal which is quite permanent. Its yellow oxide is used to impart to glass a delicate greenish-yellow tint which is accompanied by a strong fluorescence, and its black oxide is used as a pigment in porcelain painting. Symbol U. Atomic weight 239. ☞ Uranium was discovered in the state of an oxide by Klaproth in 1789, and so named in honor of Herschel's discovery of the planet Uranus in 1781.
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Century Dictionary and Cyclopedia
  • Interesting fact: One tonne of uranium produces the same amount of energy as 30,000 tonnes of coal.
    • n uranium Metallic uranium, as obtained in the fused condition by means of an electric furnace, is compact, white, and lustrous, capable of taking a high polish, of sp. gr. 18.7, melting at a very high temperature, and volatilizing more readily than iron, slowly acted upon by water at ordinary temperature, burning in oxygen or chlorin, and combining freely with nitrogen at 1000° C. The foundation was laid for the modern study of the phenomena of radioactivity when, in 1896, M. Henri Becquerel observed that a salt of uranium emits rays which affect a photographic plate screened by black paper opaque to ordinary light. This property proved to be common to all the salts of uranium and to uranium itself, and is exhibited continuously by uranium and its compounds even when they are kept in darkness. The intensity of the radiation is not materially affected by change of temperature within very wide limits. Not only are photographic effects produced by the radiation from uranium compounds, but positively or negatively electrified bodies, also, are discharged by ionization of the surrounding air. Subsequent investigation has shown that the uranium radiation is complex, and includes the emission of rays of the three types which have been designated as α, β, and γ respectively. No condensible gaseous emanation is given off, as in the case of radium and of thorium, but the radioactivity of uranium involves the constant production of a new kind of matter, itself temporarily active. See uranium X. The recent study of radioactive minerals has shown that the amount of radium in a mineral is proportional to the amount of uranium present. Uranium is believed to be the parent or generating substance of an extensive series of radioactive elements which are successively produced by the atomic disintegration of the uranium. This series of products includes ionium, actinium, radium, and polonium. The final substance remaining after the radioactive transformations are concluded is supposed to be ordinary lead.
    • n uranium Chemical symbol, U; atomic weight, 240. A metal discovered by Klaproth, in 1789, in a mineral which had been long known, and called pitch-blende, but which was supposed to be an ore of either zinc or iron. The metal itself was first isolated by Péligot, that which Klaproth had supposed to be a metal proving, on further examination, to be an oxid. Metallic uranium as obtained by the reduction of the chlorid has a specific gravity of 18.7, and resembles nickel in color. Uranium is far from being a widely distributed element; its combinations are few in number, and most of them rare. Pitch-blende is the most abundant and important of them, consisting chiefly of nranoso-uranic oxid, with usually a considerable percentage of impurities of various kinds, especially sulphuret of lead, arsenic, etc. Uranium belongs to the chromium group of elementary bodies. Sodium diuranate, or uranium-yellow, is quite an important yellow pigment, which is used on glass and porcelain, and in making yellow glass. Uranium pigments are much rarer and more expensive than those of which chromium forms the essential part.
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Chambers's Twentieth Century Dictionary
  • Interesting fact: On December 2, 1942, a nuclear chain reaction was achieved for the first time under the stands of the University of Chicago’s football stadium. The first reactor measured 30 feet wide, 32 feet long, and 21.5 feet high. It weighed 1,400 tons and contained 52 tons of uranium in the form of uranium metal and uranium oxide. Although the same process led to the massive energy release of the atomic bomb, the first artificially sustained nuclear reaction produced just enough energy to light a small flashlight.
    • n Uranium ū-rā′ni-um a very hard but moderately malleable metal, resembling nickel or iron in its lustre and colour, but in a finely comminuted state occurring as a black powder
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Webster's Revised Unabridged Dictionary
NL., from Uranus, the planet. See Uranus
Chambers's Twentieth Century Dictionary
Gr. ouranos, heaven.


In literature:

But this massive atom of uranium has a life that is computed in thousands of millions of years.
"The Story of Evolution" by Joseph McCabe
Osnome has unlimited quantities of the heaviest metals, including radium and uranium.
"Skylark Three" by Edward Elmer Smith
Go back far enough and you'd catch that uranium before it turned into lead.
"Project Mastodon" by Clifford Donald Simak
And there's been a lot of uranium taken outta there!
"A Matter of Importance" by William Fitzgerald Jenkins
It was unbelievably rich in deposits of uranium.
"The Guardians" by Irving Cox
With every source of uranium mined dry on Earth, we had tried other possibilities.
"The Hunted Heroes" by Robert Silverberg
Puranium, better than your uranium.
"Operation Earthworm" by Joe Archibald
To begin with metals, uranium melts at 1150 deg.
"Pariah Planet" by Murray Leinster
They lay gold or jewels or pots of uranium at my feet.
"Master of the Moondog" by Stanley Mullen
And no uranium for the Army next Saturday.
"Robots of the World! Arise!" by Mari Wolf

In news:

It does not take much highly enriched uranium to fabricate a small nuclear weapon.
Using a relatively simple bomb design, less than 15 pounds of such enriched uranium can produce a weapon with the explosive power of 1,000 tons of TNT.
Was uranium conversion facility the target.
Russia plans to transfer uranium fuel to an Iranian nuclear plant.
US officials wanted more enriched uranium shipped.
Czech authorities, helped by the US Department of Energy, have transferred 176 pounds of highly enriched uranium to Russia, the US Embassy in Prague said Monday.
Britain, France, Germany and the United States pressed to refer Iran to the UN Security Council after Iran announced Tuesday that it would resume uranium enrichment efforts.
In other cases, the uranium itself is in a metallic form.
Report says Iran is stockpiling enriched uranium.
Hussein 's uranium reaches Canada.
Iran has reached another milestone in its nuclear program, UN inspectors reported Friday, saying the country has completed work on an underground factory for making enriched uranium.
The latest example of failure was in April, when North Korea launched a missile two months after a supposed landmark Feb 29 agreement to halt uranium enrichment and missile launches .
US Can Accept Iran's Low-Level Uranium Enrichment.
Uranium Exposure Linked to High Lupus Rates.
Southside Virginia is home to the country's largest known uranium deposit but a 30-year ban prevents it from being mined .

In science:

Decay chains and geo-neutrino spectra from uranium and thorium 1.
Geo-neutrinos and Earth's interior
Some 80% of the geo-neutrino events are expected to arise from uranium decay chain and only 20% from thorium chain.
Geo-neutrinos and Earth's interior
The complete geo-neutrino spectrum depends on a large number of beta transitions in the uranium and thorium decay chains and it is essentially a result of theoretical calculations.
Geo-neutrinos and Earth's interior
The adopted uranium abundances in the various reservoirs are compared in Table IX.
Geo-neutrinos and Earth's interior
The separate contributions of the different reservoirs to the produced flux of geo-neutrinos from the uranium decay chain are analyzed in Table XII, from (Mantovani et al., 2004).
Geo-neutrinos and Earth's interior