Hexavalent chromium

Hexavalent chromium (chromium(VI), Cr(VI)) refers to chemical compounds that contain the element chromium in the +6 oxidation state. Virtually all chromium ore is processed via hexavalent chromium, specifically the salt sodium dichromate. Approximately 136,000 tonnes (300,000,000 lb) of hexavalent chromium was produced in 1985. Other hexavalent chromium compounds are chromium trioxide and various salts of chromate and dichromate. Hexavalent chromium is used in textile dyes, wood preservation, and as anti-corrosion and conversion coatings and a variety of niche uses. Chromium hexavalent compounds exist in several forms. Industrial uses of hexavalent chromium compounds include chromate pigments in dyes, paints, inks, and plastics; chromates added as anticorrosive agents to paints, primers, and other surface coatings; and chromic acid electroplated onto metal parts to provide a decorative or protective coating. Hexavalent chromium can be formed when performing "hot work" such as welding on stainless steel or melting chromium metal. In these situations the chromium is not originally hexavalent, but the high temperatures involved in the process result in oxidation that converts the chromium to a hexavalent state.(29 CFR OSHA General Industry 1910)

Chromium (disambiguation)

Chromium is a chemical element.

Chromium may also refer to:

See also

Chromium deficiency

Chromium deficiency is a proposed disorder that results from an insufficient dietary intake of chromium. It is an unlikely condition. Clear cases of deficiency have been observed only in hospital patients who were fed defined liquid diets intravenously for long periods of time.

Dietary guidelines

The US dietary guidelines for adequate daily chromium intake were lowered in 2001 from 50–200 µg for an adult to 30–35 µg (adult male) and to 20–25 µg (adult female). These amounts were set to be the same as the average amounts consumed by healthy individuals. Consequently, it is thought that few Americans are chromium deficient.

Chromium may fall in the same category as manganese, where it is likely that many people get too much.

Approximately 2% of ingested chromium(III) is absorbed, with the remainder being excreted in the feces. Amino acids, vitamin C and niacin may enhance the uptake of chromium from the intestinal tract. After absorption, this metal accumulates in the liver, bone, and spleen.

Tears

Tearing (/ˈtiərɪŋ/), lacrimation, or lachrymation, (from Latin lacrima, meaning "tear") is the secretion of tears, which often serves to clean and lubricate the eyes in response to an irritation of the eyes. Tears formed through crying are associated with strong internal emotions, such as sorrow, elation, emotion, love, awe or pleasure. Laughing or yawning may also lead to the production of tears.

Physiology

In humans, the tear film coating the eye, known as the precorneal film, has three distinct layers, from the most outer surface:

Having a thin tear film may prevent one's ability to wear contact lenses, as the amount of oxygen needed is higher than normal, and contact lenses stop oxygen from entering the eye. Eyes with thin tear film will dry out while wearing contact lenses. Special eye drops are available for contact lens wearers. Certain types of contact lenses are designed to let more oxygen through to the eye.

Drainage of tear film

The lacrimal glands secrete lacrimal fluid, which flows through the main excretory ducts into the space between the eyeball and lids. When the eyes blink, the lacrimal fluid is spread across the surface of the eye. Lacrimal fluid gathers in the lacrimal lake, and is drawn into the puncta by capillary action, then flows through the lacrimal canaliculi at the inner corner of the eyelids entering the lacrimal sac, then on to the nasolacrimal duct, and finally into the nasal cavity. An excess of tears, as with strong emotion, can thus cause the nose to run.

Instant Pleasure (album)

Instant Pleasure is Rockell's second album, released on October 10, 2000 on Robbins Entertainment. It is more pop oriented than her debut and was mostly produced by Tony Moran and Hex Hector. The album features the hit singles "What U Did 2 Me", "Tears" and "The Dance".

Track listing

Chart positions

Singles - Billboard (North America)

Tear

Tear may refer to:

People

Books and poetry

Games

Film

Music

Albums

Songs