Search results
Results from the WOW.Com Content Network
Typical variation of UV index by time of day and time of year, around 40.71 -74.01, based on FastRT UV Calculator [4] The UV index is a linear scale that measures the intensity of UV radiation with respect to sunburn.
The Fitzpatrick scale (also Fitzpatrick skin typing test; or Fitzpatrick phototyping scale) is a numerical classification schema for human skin color. It was developed in 1975 by American dermatologist Thomas B. Fitzpatrick as a way to estimate the response of different types of skin to ultraviolet (UV) light. [ 2 ]
Consider the sunburn, a deterministic effect: [4] when exposed to bright sunlight for only ten minutes [5] at a high UV Index, that is to say a high average dose rate, [6] the skin can turn red and painful. The same total amount of energy from indirect sunlight spread out over several years - a low average dose rate - would not cause a sunburn ...
Skin damage due to sun exposure is very wavelength dependent over the UV range 295 to 325 nm, with power at the shorter wavelength causing around 30 times as much damage as the longer one. In the calculation of UV Index , a weighting curve is used which is known as the McKinlay-Diffey Erythema action spectrum. [1]
In fact, the UV Index Scale was created by the United States Environmental Protection Agency (EPA) to help people make smart, healthy choices about sun exposure, not as a means to garner a tan.
The WHO-standard ultraviolet index is a widely publicized measurement of total strength of UV wavelengths that cause sunburn on human skin, by weighting UV exposure for action spectrum effects at a given time and location. This standard shows that most sunburn happens due to UV at wavelengths near the boundary of the UVA and UVB bands.
Standard refractive index measurements are taken at the "yellow doublet" sodium D line, with a wavelength (λ) of 589 nanometers. There are also weaker dependencies on temperature , pressure / stress , etc., as well on precise material compositions (presence of dopants , etc.); for many materials and typical conditions, however, these ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!