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A premature ventricular contraction (PVC) is a common event where the heartbeat is initiated by Purkinje fibers in the ventricles rather than by the sinoatrial node. PVCs may cause no symptoms or may be perceived as a "skipped beat" or felt as palpitations in the chest. PVCs do not usually pose any danger. [1]
CaCO 3 is used in filler masterbatch as a base with a large percentage in composition. Calcium carbonate powder accounts for 97% of the composition will bring white/opaque products more whiteness. So manufacturers can reduce the usage of white masterbatch. With a smaller percentage, calcium carbonate powder can be used for color products.
"Since the Cambrian explosion, mineralized body parts have been secreted in large quantities by biota. Because calcium carbonate, silica and calcium phosphate are the main mineral phases constituting these hard parts, biomineralization plays an important role in the global biogeochemical cycles of carbon, calcium, silicon and phosphorus" [122]
This composite material is much harder and stiffer than pure chitin, and is tougher and less brittle than pure calcium carbonate. [10] Another difference between pure and composite forms can be seen by comparing the flexible body wall of a caterpillar (mainly chitin) to the stiff, light elytron of a beetle (containing a large proportion of ...
The carbonatation process is used in the production of sugar from sugar beets.It involves the introduction of limewater (milk of lime - calcium hydroxide suspension) and carbon dioxide enriched gas into the "raw juice" (the sugar rich liquid prepared from the diffusion stage of the process) to form calcium carbonate and precipitate impurities that are then removed.
Calcium bicarbonate, also called calcium hydrogencarbonate, has the chemical formula Ca(HCO 3) 2. The term does not refer to a known solid compound; it exists only in aqueous solution containing calcium (Ca 2+), bicarbonate (HCO − 3), and carbonate (CO 2− 3) ions, together with dissolved carbon dioxide (CO 2).
However, the production of calcium carbonate drives surface alkalinity down, and in conditions of low alkalinity the CO 2 is instead released back into the atmosphere. [102] As a result of this, researchers have postulated that large blooms of coccolithophores may contribute to global warming in the short term. [ 103 ]
The principal byproduct of the Solvay process is calcium chloride (CaCl 2) in aqueous solution. The process has other waste and byproducts as well. [11] Not all of the limestone that is calcined is converted to quicklime and carbon dioxide (in reaction II); the residual calcium carbonate and other components of the limestone become wastes.