نتایج جستجو برای: solar uv
تعداد نتایج: 187362 فیلتر نتایج به سال:
background: in general, measurements of solar ultraviolet (uv) radiation are related to horizontal surfaces. while the humans walking and standing outdoors expose to the natural solar uv radiation, their eyes, cheeks, extremities, trunks, or many other anatomical sites are close to vertical plane and random orient to different directions. in this study, we characterized the diurnal variations...
anionic dbs surfactant can be photodegraded in a tio2 dispersion and h2o2 solution under an hg-lamp (15 w) uv illumination or solar exposure. degradation process has been monitored through cleavage of aromatic moiety. degradation of the detergent was small when the photolysis was carried out in the absence of tio2 and h2o2 and it was negligible in the absence of light. most of the curves repres...
background: ultraviolet (uv) radiation is divided into three regions: uva, uvb, and uvc. both the quality and quantity of solar uv radiation vary with various factors including the elevation of the sun above the horizon, as well as absorption and scattering of uv photons by molecules in the atmosphere, notably ozone and clouds. it is clear that whereas a moderate amount of uv exposure is benefi...
The reliable quantification of ultraviolet (UV) radiation at the earth’s surface requires accurate measurements of spectral global solar UV irradiance in order to determine the UV exposure to human skin and to understand long-term trends in this parameter. Array spectroradiometers (ASRMs) are small, light, robust and cost-effective instruments, and are increasingly used for spectral irradiance ...
BACKGROUND In general, measurements of solar ultraviolet (UV) radiation are related to horizontal surfaces. While the humans walking and standing outdoors expose to the natural solar UV radiation, their eyes, cheeks, extremities, trunks, or many other anatomical sites are close to vertical plane and random orient to different directions. In this study, we characterized the diurnal variations in...
The side openings of a shade structure have a direct influence on where the shade is located and the level of scattered UV in the shaded area. UV exposures were assessed for the decrease in scattered UV beneath specific shade structures by the use of two types of side-on protection, namely, polycarbonate sheeting and evergreen vegetation. Dosimetric measurements conducted in the shade of a scal...
BACKGROUND Recent US studies have raised questions as to whether geographic differences in cutaneous melanoma incidence rates are associated with differences in solar ultraviolet (UV) exposure. OBJECTIVES We sought to assess the association of solar UV exposure with melanoma incidence rates among US non-Hispanic whites. METHODS We assessed the association between county-level estimates of a...
introduction: ultraviolet (uv) radiation affects human organs such as skin, eyes and immune system, as well as animals and plants. the main natural source of uv radiation is the sun. to study the effects of solar uv radiation there is a need to quantify variations of solar energy received on the earth surface at different intervals. materials and methods: to measure uv radiation a broadband fib...
Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah,...
Aim of this study was to monitor the solar ultraviolet-B intensity and to compare the phototoxic effect of different intensity of natural and artificial ultraviolet-B on human red blood cells in presence of compounds as riboflavin and chloroquine. Photohemolysis of erythrocytes was studied under natural solar radiation and artificial ultraviolet-B radiation of 312 nm. Monitoring of solar ultrav...
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