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Topic: Ultraviolet radiation

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  ultraviolet radiation - HighBeam Encyclopedia
Much UVB and most UVC radiation is absorbed by the ozone layer of the atmosphere before it can reach the earth's surface; the depletion of this layer is increasing the amount of ultraviolet radiation that can pass through it.
Vitamin D is produced by the action of ultraviolet radiation on ergosterol, a substance present in the human skin and in some lower organisms (e.g., yeast), and treatment or prevention of rickets often includes exposure of the body to natural or artificial ultraviolet light.
The long-wavelength, "soft" ultraviolet radiation, lying just outside the visible spectrum, is often referred to as fl light; low intensity sources of this radiation are often used in mineral prospecting and in conjunction with bright-colored fluorescent pigments to produce unusual lighting effects.
www.encyclopedia.com /doc/1E1-ultravio.html   (581 words)

 Ultraviolet Radiation   (Site not responding. Last check: 2007-10-10)
Ultraviolet Radiation, electromagnetic radiation that has wavelengths in the range between 4000 angstrom units (إ), the wavelength of violet light, and 150 إ, the length of X rays.
If all the ultraviolet radiation produced by the sun were allowed to reach the surface of the earth, most life on earth would probably be destroyed.
However, ultraviolet radiation is not entirely harmful; a large portion of the vitamin D that humans and animals need for good health is produced when the human's or animal's skin is irradiated by ultraviolet rays.
library.thinkquest.org /C001429/waves/ultraviolet_radiation1.htm   (369 words)

 Highbeam Encyclopedia - Search Results for ultraviolet
ultraviolet astronomy study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers.
ultraviolet radiation invisible electromagnetic radiation between visible violet light and X rays; it ranges in wavelength from about 400 to 4 nanometers and in frequency from about 10 15 to 10 17 hertz.
Moderate exposure to ultraviolet radiation is followed by a red blush, but severe exposure may result in blisters, pain, and constitutional symptoms.
www.encyclopedia.com /SearchResults.aspx?Q=ultraviolet   (502 words)

 Ultraviolet radiation (EHC 14, 1979)
Epidemiological studies of skin cancer and ultraviolet radiation deficiency in man Non-melanoma skin cancer Malignant melanoma Identification of populations with an increased risk of skin cancer UVR deficiency 1.2.5.
Solar radiation -- the biologically active UVR spectrum Influence of stratospheric constituents Influence of clouds, haze, and smog Amount of sea level solar ultraviolet radiation in the biologically active UVR spectrum 2.1.2.
1.2.3 The relationship between ultraviolet radiation and skin cancer (a) A study is required of the effects of the interaction between UV-B and the rest of the solar spectrum in relation to DNA repair, malignant transformation, and skin tumour development.
www.inchem.org /documents/ehc/ehc/ehc014.htm   (16348 words)

 Solar and Ultraviolet Radiation (IARC Summary & Evaluation, , )
Assessment of the carcinogenicity of solar radiation for the lip is complicated by the fact that carcinoma of the lip as actually diagnosed is a mixture of cancers of the external lip and cancers of the buccal membranes.
Broad-spectrum UVR (solar-simulated radiation and ultraviolet lamps emitting mainly UVB) was tested for carcinogenicity in many studies in mice, to a lesser extent in rats and in a few experiments in hamsters, guinea-pigs, opossums and fish.
UVB radiation is mutagenic to prokaryotes and induces chromosomal aberrations in plants.
www.inchem.org /documents/iarc/vol55/solar-and-uv-radiation.html   (3593 words)

 EO Library: Ultraviolet Radiation Fact Sheet
Ultraviolet (UV) radiation that reaches the Earth’s surface is in wavelengths between 290 and 400 nm (nanometers, or billionths of a meter).
Radiation at the longer UV wavelengths of 320-400 nm, designated as UV-A, plays a helpful and essential role in formation of Vitamin D by the skin, and plays a harmful role in that it causes sunburn on human skin and cataracts in our eyes.
Ultraviolet B radiation, harmful to living organisms, represents a small portion of the spectrum, from 290 to 320 nanometer wavelengths.
earthobservatory.nasa.gov /Library/UVB   (600 words)

 Disinfection: An Overview - Ultraviolet Radiation   (Site not responding. Last check: 2007-10-10)
Ultraviolet (UV) light has long been known to have germicidal properties, but equipment and methods using it effectively in water supply systems are quite new.
UV radiation was one of the earliest recognized methods of disinfection, however its use was discontinued around the the turn of the century because of the advent of chlorination and ozonation.
Ultraviolet treatment has the advantage of adding nothing to the water while not requiring the addition of treatment materials as long as the system used is maintained in good operating condition.
www.rpi.edu /dept/chem-eng/Biotech-Environ/DISINFECT/uv.htm   (505 words)

 Ultraviolet Waves
The three regions are distinguished by how energetic the ultraviolet radiation is, and by the "wavelength" of the ultraviolet light, which is related to energy.
The near ultraviolet, abbreviated NUV, is the light closest to optical or visible light.
The extreme ultraviolet, abbreviated EUV, is the ultraviolet light closest to X-rays, and is the most energetic of the three types.
imagers.gsfc.nasa.gov /ems/uv.html   (649 words)

 Radiation Basics - Ultraviolet Radiation   (Site not responding. Last check: 2007-10-10)
Ultraviolet radiation (UVR) is defined as the portion of the electromagnetic spectrum between 100 nanometers (nm) and 400nm.
Ultraviolet radiation is classified by wavelength into three regions: UVA - Ultraviolet radiation in the range 315nm to 400nm is thought to contribute to premature aging and wrinkling of the skin and has recently been implicated as a cause of skin cancer.
Ultraviolet radiation can be produced by various artificial sources but for most people the sun is the predominant source of UVR exposure.
www.arpansa.gov.au /basics/uvr.htm   (831 words)

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Ultraviolet rays are produced by the Sun and ultraviolet lamps, such as sun lamps.
Ultraviolet light can damage living cells, but when carefully controlled, it can be used in hospitals to treat skin conditions.
Ultraviolet radiation from the sun is the main cause of skin cancer.
www.lycos.com /info/ultraviolet--ultraviolet-radiation.html?page=2   (527 words)

 Physical Agent Data Sheet/Ultraviolet Radiation
Ultraviolet (UV) is the name for a band of energy on the electromagnetic spectrum that lies between visible light and x-rays.
These threshold limit values (TLVS) refer to ultraviolet radiation in the spectral region between 200 and 400 nm and represent conditions under which it is believed that nearly all workers may be repeatedly exposed without adverse effect.
For the actinic ultraviolet spectral region (200 to 315 nm), radiant exposure incident upon the unprotected skin or eye should not exceed the values given in Table 2 within an 8-hour period.
ehsrms.uaa.alaska.edu /UVRadiationPADS.htm   (1277 words)

 Safety and Health Topics: Non-Ionizing Radiation
Non-ionizing radiation is described as a series of energy waves composed of oscillating electric and magnetic fields traveling at the speed of light.
Non-ionizing radiation is found in a wide range of occupational settings and can pose a considerable health risk to potentially exposed workers if not properly controlled.
Ultraviolet radiation (UV) has a high photon energy range and is particularly hazardous because there are usually no immediate symptoms of excessive exposure.
www.osha.gov /SLTC/radiation_nonionizing/index.html   (386 words)

 Ultraviolet (UV) Radiation
Ultraviolet (UV) "light" is a type of electromagnetic radiation.
Ultraviolet radiation lies between visible light and X-rays on the electromagnetic spectrum.
The ultraviolet spectrum is sometimes subdivided into the near UV (380 to 200 nanometer wavelengths) and extreme UV (200 to 10 nm wavelengths).
www.windows.ucar.edu /tour/link=/physical_science/magnetism/em_ultraviolet.html   (363 words)

 Ultraviolet Radiation
Ultraviolet A (UVA) is made up of wavelengths 320 to 400 nanometers (nm) in length.
Ultraviolet B (UVB) wavelengths are 280 to 320 nm in length.
Ultraviolet C (UVC) wavelengths are 100 to 280 nm in length.
www.healthsystem.virginia.edu /UVaHealth/adult_skin/ultravio.cfm   (352 words)

 Ultraviolet Radiation
Ultraviolet radiation is a form of electromagnetic energy.
The various forms of energy, or radiation, are classified according to wavelength, measured in nanometres (nm).
This means that all solar radiation travels a longer path through the atmosphere to reach the Earth, and is therefore less intense.
www.ace.mmu.ac.uk /eae/Ozone_Depletion/Older/Ultraviolet_Radiation.html   (464 words)

 Student's Guide - Ultraviolet Radiation
Simply put, ultraviolet radiation (also known as UV radiation or ultraviolet rays) is a form of energy traveling through space.
Ultraviolet radiation is more energetic than visible radiation and therefore has a shorter
However, the energy contained in ultraviolet rays is higher, so instead of just causing the molecules to shake, it actually can knock electrons away from the atoms, or causes molecules to split.
www.biospherical.com /nsf/student/page3.html   (1110 words)

 It's Your Health - Ultraviolet Radiation From the Sun
The earth's ozone layer is not as thick as it used to be and more ultraviolet radiation from the sun is reaching the Earth.
Ultraviolet radiation (UV) is a type of invisible light emitted by the sun and by certain kinds of lamps.
Overexposure to ultraviolet radiation has also been linked to a number of other health effects, including sunburns, cataracts, premature aging of the skin, and weakening of the immune system.
www.hc-sc.gc.ca /iyh-vsv/environ/ultraviolet_e.html   (1063 words)

 FACT SHEET - Ultraviolet Radiation
Ultraviolet light (UV) has two levels of radiation, ionizing and non-ionizing, which are separated by the length of waves they emit.
Non-ionizing radiation ranges from 40-400 nanometers and is the most common form of UV radiation being used in biomedical and microbiological research laboratories.
Ultraviolet Radiation is absorbed by the epidermal skin layer and usually proceeds via photochemical and thermal reactions into the dermal skin layers.
ehs.uky.edu /biosafety/uv_radiation.html   (747 words)

 Ultraviolet Radiation in the Workplace | Ontario Ministry of Labour
Ultraviolet (UV) radiation is a form of electromagnetic radiation, like radio waves, x-rays and light.
Most UV radiation sources also emit visible light; this is usually brilliant white, but it sometimes has a purplish hue.
Outdoor workers may easily be overexposed to UV radiation from the sun during spring and summer.
www.labour.gov.on.ca /english/hs/guidelines/uvradiation   (279 words)

 Ultraviolet Radiation (UVR)
Solar radiation is electromagnetic radiation emitted by the sun.
At the earth's surface it consists mainly of visible light and infrared radiation.
UVR is invisible, high-energy radiation, that is capable of causing damage to living organisms.
www.sickamongthepure.net /uvradiation.html   (134 words)

The main use of ultraviolet is in the manufacturing integrated circuits.
Artificial sources of ultraviolet light are often used to stimulate the effects of solar ultraviolet radiation in the study of the deterioration of materials on exposure to sunlight
Ultraviolet waves are used to identify materials by the glow or fluorescence under them.
www.smgaels.org /physics/uv_1.htm   (551 words)

 [No title]
From a biological viewpoint, UVB radiation is by far the most significant part of the terrestrial ultraviolet spectrum and the levels of radiation in this waveband reaching the surface of the Earth are largely controlled by ozone, a gas which comprises approximately one molecule out of every two million in the atmosphere.
In the ultraviolet, spectral irradiance falls by a factor of only two or three as the wavelength decreases from 400 to 320 nm at solar altitudes higher than 20deg., and then drops rapidly by three orders of magnitude or more from 320 to 290 nm as absorption by stratospheric ozone becomes important (figure 1).
Radiation detectors used for monitoring solar UVR are commonly designed (Robertson 1972, Berger 1976) to have a spectral sensitivity which is a close match to the action spectrum for ultraviolet-induced erythema (see figure 7).
www.ciesin.org /docs/001-503/001-503.html   (11230 words)

 UVRadiation   (Site not responding. Last check: 2007-10-10)
The manipulated variable was the ultraviolet radiation that the yeast was exposed to.
The results were that the yeast under ultraviolet radiation fermented and reached the top of each test tube faster than the yeast that was not under ultraviolet radiation.
But ultra-violet radiation is not all that harmful, vitamin D that humans and animals need to stay healthy is produced when human's or animal's skin is irradiated by ultra-violet radiation.
www.selah.k12.wa.us /MS/SciProj98/7TH/CARMELL/radiation.html   (1835 words)

 NOAA ARL Interagency Program on Ultraviolet Radiation
Ultraviolet (UV) radiation that reaches the lower atmosphere can have severe effects on exposed skin, eyes, plants, etc. Cancers can be caused, some fatal.
There are several different weighting functions that can be used, designed to mimic the response of different biological systems to different wavelengths of UV radiation, but most contemporary instruments are designed to have a spectral response function (SRF) that approximates the erythemal action spectrum of human skin, from 280 to 380 nm.
The EPA intramural research focuses on the interactive effects of climate change and UV radiation on nutrient and carbon cycles in coastal waters of the Southeast and the role of UV exposure in amphibian deformities and declines through laboratory and field studies.
www.arl.noaa.gov /research/programs/uv.html   (2295 words)

 Ultraviolet radiation definition - Medical Dictionary definitions of popular medical terms
Ultraviolet radiation is made up of three types of rays -- ultraviolet A, ultraviolet B, and ultraviolet C. Although ultraviolet C is the most dangerous type of ultraviolet light in terms of its potential to harm life on earth, it cannot penetrate earth's protective ozone layer.
Ultraviolet A and ultraviolet B, on the other hand, do penetrate the ozone layer in attenuated form and reach the surface of the planet.
Because ultraviolet A is weaker than ultraviolet B, scientists long blamed ultraviolet B as the sole culprit in causing skin cancer in persons with a history of sunburn and repeated overexposure to ultraviolet radiation.
www.medterms.com /script/main/art.asp?articlekey=5898   (424 words)

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