Research Results For 'Silica'

HARD-PORCELAIN

Hard-porcelain is one of two types of porcelain composed of a natural clay containing kaolin and a compound of silica and lime.
Research Hard-Porcelain

OCHRE

Ochre is a yellow earth pigment derived from sands and clays around the world. Ochre consists of a mixture of silica, alumina and hydrated iron oxide. Ochre is one of the oldest pigments known to man, and produces a dull brownish-yellow effect which is stable, permanent and fast to light.
Research Ochre

DEMOSPONGIA

The demospongia is a class of sponges with a skeleton of four-rayed spicules made of silica, or sponging fibres, or no skeleton at all.
Research Demospongia

HEXACTINELLIDA

Hexactinellida is a class of sponge with a skeleton built of six-rayed spicules made of silica.
Research Hexactinellida

SPONGE

Sponges (Porifera) are a group of simple animals. They possess a porous ' spongy' texture and no definite external organs or form. They vary in shape and hardness. The sponge body consists of a mass of cells of various kinds forming a delicate tissue, and this is supported on a skeleton of minute rods, or spicules, of calcite, silica or of a horny organic substance.
Research Sponge

SILICOSIS

Silicosis is an occupational disease (pneumoconiosis) caused by the inhalation of silica dust which causes small concentrations of inflammation and scarring of the lungs. Over time the result of silicosis is shortness of breath, and increased susceptibility to infection of the lungs. Silicosis particularly affects miners and those working with stone.
Research Silicosis

HYDROFLUORIC ACID

Hydrofluoric acid, fluohydric acid or hydrogen flouride is a strong acid obtained by the action of concentrated sulphuric acid on fluorspar in a leaden vessel, which, though monobasic, forms double salts of the alkali metals by union of a molecule of salt and of acid. Hydrofluoric acid is a solvent of silica and silicates. Hydrofluoric acid is obtained in aqueous solution by heating calcium fluoride with concentrated sulphuric acid and condensing the gas given off in water.

The anhydrous acid is a colourless liquid, with a boiling-point just above the ordinary temperature. It is usually used in aqueous solution, and is kept in caoutchouc bottles. It blisters the skin and is used for etching glass. When the vapour is used the etching is transparent, but with the solution it is dull. The glass to be etched is coated with a thin layer of wax, and the design traced with a fine pointed instrument, and after etching the wax is dissolved away and the design becomes visible. Hydrofluoric acid is also used to decompose and dissolve silicates in mineral analysis.
Research Hydrofluoric Acid

KRYPTON

Krypton, named from the Greek word kryptos, meaning 'hidden', is an odourless, colourless, tasteless, non-toxic, monatomic, and highly stable gaseous element of the noble gases group with the symbol Kr. The concentration of Krypton gas in the atmosphere by volume is 1.1 x 10-4. Traces of krypton are present in minerals and meteorites, but the usual commercial source is the atmosphere, which contains 1.14 parts per 106 by volume. Krypton also is formed by the nuclear fission of uranium triggered by slow neutrons: this source may be expected to become increasingly important because of the growing number of fission-power plants.

Krypton has isotopes of every mass number from 74 through 95; six, with mass numbers 78, 80, 82, 83, 84, and 86, are stable. After it has been stored a few days, krypton obtained by nuclear fission contains only one radioactive isotope, krypton-85, which has a half-life of about 10 years, because all the other radioactive isotopes have half-lives of three hours or less. Because its boiling point is about 30 degrees C higher than those of the major constituents of air,
krypton is readily separated from liquid air by fractional distillation; it accumulates along with xenon in the least volatile portion. These two gases are further purified by adsorption onto silica gel, redistillation, and passage over hot titanium metal, which removes all impurities except other noble gases.

Krypton gas liquefies at -152.30 degrees C and freezes 4 degrees C lower. When a current of electricity is passed through a glass tube containing krypton at low pressure, a bluish white light is emitted. The wavelength of an orange-red component of light emitted by stable
krypton-86, because of its extreme sharpness, served as the international standard for the metre from 1960 to 1983. (One metre equals 1,650,763.73 times the wavelength of this line).
Krypton gas is principally shipped and used in gaseous form for excimer lasers, light bulbs, window insulation and Research and Development laboratory research.
Research Krypton

OCHRE

Ochre is a yellow earth pigment derived from sands and clays found around the world, consisting of a mixture of silica, alumina, and hydrated iron oxide. Ochre has been used as a pigment since the earliest times and produces a brownish yellow, stable stain which is fast to light.
Research Ochre

RAW SIENNA

Raw sienna is a yellow-brown earth colour consisting chiefly of iron oxide and containing smaller amounts of silica, alumina, manganese oxide and calcium carbonate. Raw sienna is found mainly in Italy and Sicily, and gets its name from the Italian town of Sienna. Raw sienna is a somehat transparent, golden yellow pigment.
Research Raw Sienna

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