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 degradation sunscreen products, which protect skin from UV attack. They are used frequently in plastics, including cosmetics and films. Different UV stabilizers are utilized depending upon the substrate, intended functional life, and sensitivity to UV degradation. UV stabilizers, such as benzophenones, work by absorbing the UV radiation and preventing the formation of free radicals. Depending upon substitution, the UV absorption spectrum is changed to match the application. Concentrations normally range from 0.05% to 2%, with some applications up to 5%. Frequently, glass can be a better alternative to polymers when it comes to UV degradation. Most of the commonly used glass