Effects of UV Radiation

The outdoor durability of a fluorinated coating is directly related to its fluorine content and is assessed by gloss retention [51], 

The degradation of some fluoropolymers outdoors occurs very slowly and can be detected only by very sensitive analytical methods, such as x-ray photoelectron spectroscopy (XPS) [52] or electron spin resonance (ESR) spectroscopy [53], 

Scheirs, J., in Modem Fluoropolymers (Scheirs, J., Ed.), John Wiley Sons, Ltd, Chichester, UK, p. 49 (1997). 

Gangal, S. V., in Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 11, 3rd ed., John Wiley Sons, New York, p. 11 (1980). 

Carlson, D. P. and Schmiegel, W., Fluoropolymers, organic, in Ullmann s Encyclopedia of Industrial Chemistry, Vol. All, VCH Publishers, Weinheim, West Germany, p. 39 

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The effects of uv radiation on V/-nitroso compounds depend on the pH and the medium. Under neutral conditions and ia the absence of radical scavengers, these compounds often appear chemically stable, although the E—Z equiUbrium, with respect to rotation around the N—N bond, can be affected (70). This apparent stabiUty is due to rapid recombination of aminyl radicals and nitric oxide [10102-43-9] formed duting photolysis. In the presence of radical scavengers nitrosamines decay rapidly (71). At lower pH, a variety of photoproducts are formed, including compounds attributed to photoelimination, photoreduction, and photo-oxidation (69). Low concentrations of most nitrosamines, even at neutral pH, can be eliminated by prolonged kradiation at 366 nm. This technique is used ki the identification of /V-nitrosamines that are present ki low concentrations ki complex mixtures (72). 

The effects of UV radiation on degradable plastics are usually confined to the exposed surface layers. Tlie general effect is one of embrittlement. Tensile strength may either increase or decrease, but the elongation upon breaking is always reduced. A loss of impact... 

Figure 2. Schematic drawing of the four experimental tanks and chambers used to investigate the effects of UV radiation of Antarctic phytoplankton and ice-algae. (Reproduced with permission from reference 23. Copyright 1990 Springer-Verlag, Berlin.)...

Effect of UV on Productivity of the Southern Ocean. Has ozone depletion over Antarctica affected the productivity of the Southern Ocean There is no easy answer. First, one has to take into account the fact that the drastic decrease of ozone over Antarctica has been reported as recently as 1976, a relatively short time in the evolution of the organisms to develop mechanisms to cope with elevated UV. One of the most vexing problems in studying the effects of UV radiation on productivity, is a dearth of historical data on the level of UV. Without these baselines, normal fluctuations could easily be interpreted as decline in productivity. Second, there is a host of biotic and abiotic factors that play significant roles in governing the productivity of the Southern Ocean (40). Ultraviolet radiation is but one more complicating factor to be considered in an already stressful environment. 

Although in this chapter we have focused on the potential effects of increased UV-B radiation on the Antarctic marine ecosystem, our results also have bearing on efforts to describe the effects of UV radiation on global marine productivity. However, here again, considerable uncertainties still remain in assessing the effects of ozone depletion on global production. Several authors have predicted a... 

This data led to the development of the original method of protecting the DNA from the damaging effects of UV radiation with a wavelength X = 254 nm for detection of the results of gel electrophoresis. It is demonstrated the benefits of the adding of the C6-AR in... 

Effect of UV Radiation on Sodium Pentachlorophenate. Sodium pentachlorophenate is quickly degraded in the presence of ultraviolet light as well as daylight, as shown in Table III. The degradation is almost complete after 16 hours exposure to the General Electric R.S. sunlamp. Three and one-half days of rainy and overcast skies account for the somewhat lower degradation observed in the sample exposed to daylight. 

Sawada, M., J.C. Carlson, and H.E. Enesco. 1990. The effects of UV radiation and antioxidants on life span and lipid peroxidation in the rotifer Asplanchna brightwelli. Arch. Gerontol. Geriatr. 10 27-36. 

Hemmi A, Makinen A, Jormalainen V, Honkanen T (2005) Responses of growth and phlorotannins in Fucus vesiculosus to nutrient enrichment and herbivory. Aquat Ecol 39 201 -211 Henry BE, Van Alstyne KL (2004) Effects of UV radiation on growth and phlorotannins in Fucus gardneri (Phaeophyceae) juveniles and embryos. J Phycol 40 527-533 Herms DA, Mattson WJ (1992) The dilemma of plants to grow or to defend. Q Rev Biol 67 283-335... 

Karsten U, Bischof K, Flanelt D, Tug H, Wiencke C (1999) The effect of UV-radiation on photosynthesis and UV-absorbing substances in the endemic Arctic macroalga Devaleraea ramen-tacea (Rhodophyta). Physiol Plant 105 58-66... 

Measured total column ozone has fallen between about 1970 and 1994. Ultraviolet irradiation increases at the surface of the earth due to ozone depletion should peak at about 15% in midlatitudes. The incidence of harmful health effects of UV radiation can be expected to rise, eventually, at midlatitudes. Public health action is still necessary to reduce sun exposure, increase protection against the sun, and develop clear policies on the action that should be taken on early detection and treatment of skin cancers (Armstrong, 1997). 

The effect of UV radiation on other azides was conducted by Muller and Brous on Na azide (Ref 8), by Garner and Maggs on Ba and Sr azides (Ref 16), by Mott on metallic azides (Ref 17), and by Boldyrev and Skorik on Ag and Ba azides (Ref 144). With Na, Sr and Ba azides, each are decompd by UV light at room temp and the thermal decompn of these materials is accelerated by pre-irradiation. Boldyrev et al found that irradiating Ag azide with UV light or X-rays at the instant of decompn had no effect on the rate of its thermal decompn... 

The effect of UV radiation on the sensitivity of Pb azide was pursued by Abel and Levy (Ref 153) who observed that changes occurred in the impact and thermal sensitivity of colloidal Pb azide. The effects can be seen in Fig 18 where the 50% point was lowered significantly before returning near its original height as a function of... 

Mopper, K., and D. J. Kieber. 2000. Marine photochemistry and its impact on carbon cycling. In The Effects of UV Radiation in the Marine Environment (S. deMora, S. Demers, and M. Vernet, Eds.), pp. 101-129. Cambridge Univ. Press, Cambridge, UK. 

Tranvik, L., and S. Kokalj. 1998. Decreased biodegradability of algal DOC due to interactive effects of UV radiation and humic matter. Aquatic Microbial Ecology 14 301-307. 

Miller, W. L. 1998. Effects of UV radiation on aquatic humus Photochemical principles and experimental considerations. In Aquatic Humic Substances (D. O. Hessen, and L. J. Tranvik, Eds.), pp. 125-144. Springer-Verlag, Berlin. 

Perez-Rodriguez, E., Gomez, I., Karsten, U., and Figueroa, F. L., Effects of UV radiation on photosynthesis and excretion of UV-absorbing compounds of Dasycladus vermicularis (Dasycladales, Chlorophyta) from southern Spain, Phycologia, 37, 379, 1998. 

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