Thermosphere gas and the ionospheric plasma. The International Space Station orbits the Earth within the middle of the thermosphere, between . It is convenient to separate the atmospheric regions according to the two temperature minima at about 12 km altitude (the tropopause) and at about 85 km (the mesopause) (Figure 1). The thermosphere (or the upper atmosphere) is the height region above 85 km, while the region between the tropopause and the mesopause is the middle atmosphere (stratosphere and mesosphere) where absorption of solar UV radiation generates the temperature maximum near 45 km altitude and causes the ozone layer. The density
UV marker blood or even urine. Modern UV-invisible ink is mainly made by a fluorescent derived from things in nature that glow when exposed to an ultraviolet light. The main components include dilute laundry detergent, body fluids, tonic water and vitamin B-12 dissolved in vinegar. There are different types of UV-invisible ink: opaque, semi-opaque and translucent. All of the three contain acrylic monomers which contain a diluent and a photoinitiator to participate in the curing reaction and to respond to UV radiation. Photoinitiators is a very important element for making the ink as it is the substance that absorbs the UV mission