Period 6 element devices though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favor of alcohol-filled, galinstan-filled, digital, or thermistor-based instruments. It remains in use in scientific research applications and in amalgam material for dental restoration. It is used in lighting: electricity passed through mercury vapor in a phosphor tube produces short-wave ultraviolet light which then causes the phosphor to fluoresce, making visible light. Thallium is a chemical element with the symbol Tl and atomic number 81. This soft gray other metal resembles tin but discolors when exposed to air. The
Ship disposal Ship disposal A number of different methods exist for disposing of a ship after it has reached the end of its effective or economic service life with an organisation. Although many options are technically possible, some, such as deep water sinking, are not used for non-military vessels, or have come under increased scrutiny. Options currently available include: Some shipping companies have in the past attempted to dispose of their ships illegally, often due to the high costs of sanitizing these ships in a legal way as a result of the presence of large quantities of toxic compounds and materials. Prominent