Cobalt

In the third quarter of 2003 Sun discountinued their Cobalt line in favor of the AMD based Sun Fire line. The tallest cross, at 152.4 meters high, is part of Francisco Franco's monumental "Valley of the Fallen", the Monumento Nacional de Santa Cruz del Valle de los Caidos in Spain. Previously known as Cobalt Systems, this Internet appliance company was acquired by Sun in 2000. The Crux, or Southern Cross, is a cross-shaped a constellation in the Southern Hemisphere. Cobalt was also the name of Sun Microsystems' mainly rack-mounted, Intel and Linux based, server appliance line. Several flags have crosses, including all the nations of Scandinavia, whose crosses are known as Scandinavian crosses, and many nations in the Southern Hemisphere, which incorporate the Southern Cross. This process is referred to as irradiation.
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Nevertheless, the gamma radiation emitted from cobalt-60 is used to kill bacteria on fruit and vegetables thus increasing their shelf life. The semi-classic book "A Glossary of Terms Used in Heraldry" by James Parker (1894) is online, and contains much information about variants of crosses used in heraldry. The risk in the absence of a nuclear war comes from improper handling (or theft) of medical radiotherapeutic units. See also: Anchored Cross, Cross barby (barbée), Fylfot. Some nuclear weapon designs could intentionally increase the amount of Cobalt-60 dispersed as nuclear fallout – this is sometimes called a dirty bomb or cobalt bomb, once predicted by a leading scientist as being capable of wiping out all life on earth. See heraldry for background information. Cobalt-60 is a risk factor in a nuclear confrontation because neutron emissions will convert iron into this isotope. There are numerous other variations on the cross in heraldry.

Ingestion of ⁶⁰Co will lead to incorporation of some cobalt into tissues, which is released very slowly. Crosses that are used in heraldry but also commonly in other contexts are not listed here. Cobalt-60 is a powerful gamma ray emitter and exposure to ⁶⁰Co is therefore a cancer risk. These crosses are ones used exclusively or primarily in heraldry, and do not necessarily have any special meanings commonly associated with them. Cobalt compounds should be handled with care due to cobalt's slight toxicity. A large cross through a text often means that it is wrong or should be considered deleted. Powdered cobalt in metal form is a fire hazard. It also allows marking a position more accurately than a large dot.

The primary decay products before ⁵⁹Co are element 26 (iron) isotopes and the primary products after are element 28 (nickel) isotopes. A cross is often used as a check mark because it can be clearer, easier to create with an ordinary pen or pencil, and less obscuring of the text or image that is already present than a large dot. The primary decay mode before the most abundant stable isotope, ⁵⁹Co, is electron capture and the primary mode after is beta decay. Written crosses are used for many different purposes, particularly in mathematics. The isotopes of cobalt range in atomic weight from 50 amu (⁵⁰Co) to 73 amu (⁷³Co). Named animal, the symbol was found in the plans of temples, with the pillars from above looking like an additional cross. This element also has 4 meta states, all of which have half lives less than 15 minutes. In old Armenian temples, some stylistic Turkic influences are found in cross symbols.

All of the remaining radioactive isotopes have half-lifes that are less than 18 hours and the majority of these have half lives that are less than 1 second. The first Christian books from Armenia and Syria contained evidence that the cross originated with horsemen from the east, possibly referring to the first Turkic people. 22 radioisotopes have been characterized with the most stable being ⁶⁰Co with a half-life of 5.2714 years, 57-Co (⁵⁷Co) with a half-life of 271.79 days, and 56-Co (⁵⁶Co) with a half-life of 77.27 days, and 58-Co (⁵⁸Co) with a half life of 70.86 days. The cross in the old Altaic religion called Tengriism symbolizes the god Tengri; it wasn't an elongated "dagger" cross, instead resembling a plus sign (+). Naturally occurring cobalt is composed of 1 stable isotope, 59-Co (⁵⁹Co). Other early images of crosses were found in the Central Asian steppes, and some were found in Altay. Oxides are antiferromagnetic at low temperature CoO (Neel temperature: 291 K) and Co₃O₄ (Neel temperature: 40 K). Like other symbols from this period, their use continued in the Celtic cultures in Europe.

Due to the various oxidation states, there is an abundant number of compounds. There are many cross-shaped incisions in European cult caves, dating back to the earliest stages of human cultural development in the stoneage. It is also produced in the town of Cobalt, Ontario as a byproduct of the silver mining. It is not known when the first cross image was made; after circles, crosses are one of the first symbols drawn by children of all cultures. It is also found in Finland, Azerbaijan, and Kazakhstan. . The world's major producers of cobalt are the Democratic Republic of the Congo, mainland China, Zambia, Russia and Australia. It is frequently a representation of the division of the world into four elements (or cardinal points), or alternately as the union of the concepts of divinity, the vertical line, and the world, the horizontal line (Koch, 1955).

The main ores of cobalt are cobaltite, erythrite, glaucodot, and skutterudite. The cross is one of the most ancient human symbols, and is used by many religions, most notably Christianity. Cobalt is usually not mined alone, and tends to be produced as a by-product of nickel and copper mining activities. The lines usually run vertically and horizontally; if they run diagonally, the design is technically termed a saltire. Cobalt is not found as a free metal and is generally found in the form of ores. A cross is a geometrical figure consisting of two lines or bars intersecting each other at a 90° angle, dividing one or two of the lines in half. Cobalt is a central component of the vitamin cobalamin, or vitamin B-12. If n≥1 is an integer, the numbers coprime to n, taken modulo n, form a group with multiplication as operation; it is written as (Z/nZ)^× or Z_n^*.

Having 0.13 to 0.30 mg/kg of cobalt in soils markedly improves the health of grazing animals. The addition (or plus) sign (+) and the multiplication (or times) sign (×). Cobalt in small amounts is essential to many living organisms, including humans. The dagger or obelus (†). Some also think the name may derive from Greek kobalos, which means 'mine', and which may have common roots with kobold, goblin, and cobalt. The Chinese character for ten is 十 (see Chinese numerals). Other sources cite the origin as stemming from silver miners' belief that cobalt had been placed by kobolds who had stolen the silver. In the Latin alphabet, the letter X and the miniscule form of T are crosses.

The word cobalt comes from the German kobalt or kobold, meaning evil spirit, the metal being so called by miners, because it was poisonous and troublesome (it polluted and degraded the other mined elements, like nickel). The Roman numeral for ten is X. In 1938, John Livingood and Glenn Seaborg discovered cobalt-60. During the 19th century, cobalt blue was produced at the Norwegian Blaafarveværket (70-80 % of world production), led by the Prussian industrialist Benjamin Wegner. He was able to show that cobalt was the source of the blue color in glasses, which previously had been attributed to the bismuth found with cobalt.

The date of discovery varies depending on the source, but is between 1730 and 1737. George Brandt (1694-1768) is credited with the discovery of cobalt. Cobalt was known in ancient times through its compounds, which would color glass a rich blue. The second machine is out beside the walkway into the Centre.

In fact the first machine is on display in the Saskatoon Cancer Centre – look up when entering the lobby. The first ⁶⁰Co therapy machine (the "cobalt bomb") was built and first used in Canada. The ⁶⁰Co source is useful for about 5 years but even after this point is still very radioactive, and so cobalt machines have fallen from favor in the Western world where linacs are common. The metal has the unfortunate habit of producing a fine dust, causing problems with radiation protection.

The ⁶⁰Co source is about 2 cm in diameter and as a result produces a geometric penumbra, making the edge of the radiation field fuzzy. It produces two gamma rays with energies of 1.17 MeV and 1.33 MeV. Cobalt-60 (Co-60 or ⁶⁰Co) is a radioactive metal that is used in radiotherapy. Co-60 is useful as a gamma ray source partially because it can be produced - in known quantity, and very large amounts - by simply exposing natural cobalt to neutrons in a reactor for a given time.

Common oxidation states of cobalt include +2, and +3, though +1 is also seen. Metallic cobalt commonly presents a mixture of two crystallographic structures hcp and fcc with a transition temperature hcp→fcc of 722 K. Cobalt has a relative permeability two thirds that of iron. Cobalt-60, an artificially produced radioactive isotope of cobalt, is an important radioactive tracer and cancer-treatment agent.

Mammals require small amounts of cobalt salts. It is frequently associated with nickel, and both are characteristic ingredients of meteoric iron. The Curie temperature is of 1388 K with 1.6~1.7 Bohr magnetons per atom. Cobalt is a hard ferromagnetic silver-white element.

. Cobalt is a chemical element in the periodic table that has the symbol Co and atomic number 27. London celebrates 50 years of Cobalt-60 Radiotherapy. WebElements.com – Cobalt.

National Pollutant Inventory - Cobalt fact sheet. Cobalt is the name of a current line of cars from Chevrolet. Los Alamos National Laboratory - Cobalt. It is used in industrial radiography to detect structural flaws in metal parts.

It is used in radiation treatment of foods for sterilization (cold pasteurization). It is used in radiotherapy. Cobalt-60 has multiple uses as a gamma ray source: