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
Active safety events in a favourable manner. In the automotive sector the term active safety (or primary safety) refers to safety systems that are active "prior" to an accident. This has traditionally referred to non-complex systems such as good visibility from the vehicle and low interior noise levels. Nowadays, however, this area contains highly advanced systems such as anti-lock braking system, electronic stability control and collision warning/avoidance through automatic braking. This compares with passive safety (or secondary safety), which are active "during" an accident. To this category belong seat belts, deformation zones and air-bags, etc. Advancement in passive safety systems has progressed