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Depyrogenation refers to the removal of pyrogens from solutions, most commonly from injectable pharmaceuticals.. A pyrogen is defined as any substance that can cause a fever. . Bacterial pyrogens include endotoxins and exotoxins, although many pyrogens are endogenous to the ho
The optional second step (for bare silicon wafers) is a short immersion in a 1:100 or 1:50 solution of aqueous HF (hydrofluoric acid) at 25 °C for about fifteen seconds, in order to remove the thin oxide layer and some fraction of ionic contaminants. If this step is performed without ultra high purity materials and ultra clean containers, it ...
Conservation-restoration is the practice of cleaning and discovering the original state of an object, investigating the proper treatments and applying those treatments to restore the object to its original state without permanently altering the object, and then preserving the object to prevent further deterioration for generations to come (Caple, p. 5-6). [1]
That step reduces nitric acid (see decomposition of aqua regia). If elemental gold is desired, it may be selectively reduced with reducing agents such as sulfur dioxide , hydrazine , oxalic acid , etc. [ 3 ] The equation for the reduction of oxidized gold ( Au 3+ ) by sulfur dioxide ( SO 2 ) is the following:
Glass disease, also referred to as sick glass or glass illness, is a degradation process of glass that can result in weeping, crizzling, spalling, cracking and fragmentation. [ 1 ] [ 2 ] Glass disease is caused by an inherent instability in the chemical composition of the original glass formula. [ 3 ]
If you see estate sale listings with lots of glassware, she says, there's probably a piece or two of uranium glass hiding amongst the others. Whitney Granger’s ring collection. Whitney Granger
In an additional processing step, smaller sodium ions in the surface layer of the glass are replaced by larger potassium ions, which increases the tension in the glass surface, making it stronger. [7] This technique is also used to make Gorilla Glass. [6]
Amused, Beauchamp took it a step further, asking the bot to write a poem about a useless chatbot, and criticize the company. Unlike locating a missing parcel, the bot had no issue doing these things.