chemical methods ( actinometry ) depend on the measurement of the extent to which a chemical reaction occurs under the influence of uv light. two chemical actinometers have been used in this research. in one method, the mixtures of potassium peroxidisuiphate butanol solutions were irradiated for various time intervals, and ph-changes were determined. a linear relationship was observed between t...

background : one way to optimize energy consumption is replacing incandescent lamp with compact fluorescent lamps .these lamps produce ultraviolet radiation due to the nature of light production. this study aimed to evaluate the ultraviolet radiation emitted from compact fluorescent lamps which are widely used in iran. methods : this study carries out on 16 compact fluorescent lamps (four diffe...

drought, ultraviolet radiation and atmospheric co2 are some three environmental factors that seriously affect future food security. the objective followed in the present research was to study the effect of two levels of carbon dioxide (400 and 900 ppm), ultraviolet radiation (uv a, b and c with intensities of 18, 25 and 40 microw.cm-2 respectively) and water deficit (%100 and %60 of field capac...

background: wearing spectacles is the most common approach in correcting the refractive errors worldwide. due to harmful effects of overexposure to solar ultraviolet radiations, the usage of multi-layer coatings in ophthalmic lenses has recently been increased. these lenses can reduce the reflections and hence increase the transmission of visible light; they can also decrease the transmission o...

background: light is an important and adjustable physical factor in the job environment.this study aimed to determine the intensity of natural and mixed light and also the level of ultraviolet radiation in libraries and computer sites of ilam universities in spring 2011.   methods: in this cross-sectional study, 10 libraries, 16 study saloons, and 7 computer sites were selected. luminosity asse...

background: atrazine is one of the most widely used triazine herbicides which has been used for controlling broadleaf and grassy weeds for many years. its widespread use in water has caused environmental concern because of frequent detection of atrazine in aquatic systems where this herbicide has been spilled. therefore, the purpose of this study was to determine the herbicide removal efficienc...

rhabditidae is a family of free-living nematodes. free living nematodes due to their active movement and resistance to chlorination, do not remove in conventional water treatment processes thus can be entered to distribution systems and cause adverse health effects. ultraviolet radiation (uv) can be used as a method of inactivating for these organisms. this cross sectional study was done to inv...

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...

background: the goal was to upgrade and/or uprate the traditional non-contact array by producing few modifications in the configuration of this model in order to maximize light receiving of water from the uv lamp and a better disinfection.  methods: an innovative non-contact model was made with a design based on irradiation of water, which was flowing as two thin waterfalls around a uv lamp in ...

The ultraviolet radiation present in sunlight is immune suppressive. Recently we showed that solar-simulated ultraviolet radiation (ultraviolet A + B; 295-400 nm), applied after immunization, suppressed immunologic memory and the elicitation of delayed-type hypersensitivity to the common opportunistic pathogen, Candida albicans. Further, we found that wavelengths in the ultraviolet A region of ...