Exposure to solar UV in Finland

Energy Technology Data Exchange (ETDEWEB)

Jokela, K.; Leszczynski, K.; Visuri, R.; Ylianttila, L. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

1995-12-31

Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

Interrelations of UV-global/global/diffuse solar irradiance components and UV-global attenuation on air pollution episode days in Athens, Greece

International Nuclear Information System (INIS)

Koronakis, P.S.; Sfantos, G.K.

2002-01-01

An investigation of global ultraviolet (G UV ), global (G) and diffuse (G d ) solar intensities, continuously recorded over a period of five years at a station in Athens, Greece, and stored on the basis of hourly time intervals since 1996, has revealed the following: (a) UV-global irradiation, associated with the 290-395 nm wavelength region, constitutes 4.1% of global solar. (b) UV-global irradiance ranges from an average minimum of 2.4 W m -2 and 3.1% of global solar in January to an average maximum of 45 W m -2 and 7.8%, respectively, in June, both considered at 13:00, solar time. (c) There exists a good correlation among the two dimensionless irradiance ratios G UV /G d and G d /G in the form of an exponential relationship. (d) UV-global monthly irradiation data show evidence of temporal variability in Athens, from 1996 to 2000. (e) Anthropogenic and photochemical atmospheric pollutant agents (O 3 , CO, SO 2 , NO x , smoke) causing air pollution episodes seem to affect differently solar irradiance components. The main results of analysis (measurements within ± 2 h from solar noon) indicate that a buildup of O 3 and NO x inside the urban Athens plume during cloudless and windless warm days could cause: (i) UV-global irradiance depletion between 5.4% and 14.4%. (ii) Diffuse solar irradiance enhancement up to 38.1%. (iii) Global solar irradiance attenuation ranging up to 6.3%. (author)

UV radiation hardness of silicon inversion layer solar cells

International Nuclear Information System (INIS)

Hezel, R.

1990-01-01

For full utilization of the high spectral response of inversion layer solar cells in the very-short-wavelength range of the solar spectrum sufficient ultraviolet-radiation hardness is required. In addition to the charge-induced passivation achieved by cesium incorporation into the silicon nitride AR coating, in this paper the following means for further drastic reduction of UV light-induced effects in inversion layer solar cells without encapsulation are introduced and interpretations are given: increasing the nitride deposition temperature, silicon surface oxidation at low temperatures, and texture etching and using higher substrate resistivities. High UV radiation tolerance and improvement of the cell efficiency could be obtained simultaneously

Effects of solar UV radiation on diatom assemblages of the Mediterranean

International Nuclear Information System (INIS)

Santas, Regas; Lianou, Charalambia; Haeder, D.-P.

1996-01-01

Three UV treatments (PAR; PAR + UVA; PAR + UVA + UVB) were performed by placing different UV-absorbing filters over communities developing on ceramic tiles in a natural marine habitat near Korinthos, Greece. The experiment was repeated at three depths (0.5 m, 1 m, 1.5 m) below the surface of the sea. Differences in community structure due to UV radiation exposure were more pronounced during the early stages of community development. After the first 3 weeks of growth, the productivity of the PAR + UVA + UVB treatment was significantly lower than the PAR + UVA but not than the PAR treatment. This difference did not persist thereafter. At 5 weeks of growth, the productivity at 0.5 m was significantly lower than at 1.0 m. No other significant differences were observed. The findings of the present study suggest that periphytic communities occurring at the upper layers of the euphotic zone may be capable of adjusting to changes in environmental stresses such as by increased solar UVB irradiance. (Author)

Inhibitory effects of ambient levels of solar UV-A and UV-B radiation on growth of cucumber

International Nuclear Information System (INIS)

Krizek, D.T.; Mirecki, R.M.; Britz, S.J.

1997-01-01

The influence of solar UV-A and UV-B radiation at Beltsville, Maryland, on growth and flavonoid content in four cultivars of Cucumis sativus L. (Ashley, Poinsett, Marketmore, and Salad Bush cucumber) was examined during the summers of 1994 and 1995. Plants were grown from seed in UV exclusion chambers consisting of UV-transmitting Plexiglas, lined with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or cellulose acetate to transmit UV-A and UV-B. Despite previously determined differences in sensitivity to supplemental UV-B radiation, all four cultivars responded similarly to UV-B exclusion treatment. After 19–21 days, the four cultivars grown in the absence of solar UV-B (polyester) had an average of 34, 55, and 40% greater biomass of leaves, stems, and roots, respectively, 27% greater stem height, and 35% greater leaf area than those grown under ambient UV-B (cellulose acetate). Plants protected from UV-A radiation as well (Llumar) showed an additional 14 and 22% average increase, respectively, in biomass of leaves and stems, and a 22 and 19% average increase, respectively, in stem elongation and leaf area over those grown under polyester. These findings demonstrate the extreme sensitivity of cucumber not only to present levels of UV-B but also to UV-A and suggest that even small changes in ozone depletion may have important biological consequences for certain plant species. (author)

UV spectra, bombs, and the solar atmosphere

OpenAIRE

Judge, Philip G.

2015-01-01

A recent analysis of UV data from the Interface Region Imaging Spectrograph {\\em IRIS} reports plasma "bombs" with temperatures near \\hot{} within the solar photosphere. This is a curious result, firstly because most bomb plasma pressures $p$ (the largest reported case exceeds $10^3$ dyn~cm$^{-2}$) fall well below photospheric pressures ($> 7\\times10^3$), and secondly, UV radiation cannot easily escape from the photosphere. In the present paper the {\\em IRIS} data is independently analyzed. I...

Growth enhancement of soybean (Glycine max) upon exclusion of UV-B and UV-B/A components of solar radiation: characterization of photosynthetic parameters in leaves.

Science.gov (United States)

Guruprasad, Kadur; Kadur, Guruprasad; Bhattacharjee, Swapan; Swapan, Bhattacharjee; Kataria, Sunita; Sunita, Kataria; Yadav, Sanjeev; Sanjeev, Yadav; Tiwari, Arjun; Arjun, Tiwari; Baroniya, Sanjay; Sanjay, Baroniya; Rajiv, Abhinav; Abhinav, Rajiv; Mohanty, Prasanna

2007-01-01

Exclusion of UV (280-380 nm) radiation from the solar spectrum can be an important tool to assess the impact of ambient UV radiation on plant growth and performance of crop plants. The effect of exclusion of UV-B and UV-A from solar radiation on the growth and photosynthetic components in soybean (Glycine max) leaves were investigated. Exclusion of solar UV-B and UV-B/A radiation, enhanced the fresh weight, dry weight, leaf area as well as induced a dramatic increase in plant height, which reflected a net increase in biomass. Dry weight increase per unit leaf area was quite significant upon both UV-B and UV-B/A exclusion from the solar spectrum. However, no changes in chlorophyll a and b contents were observed by exclusion of solar UV radiation but the content of carotenoids was significantly (34-46%) lowered. Analysis of chlorophyll (Chl) fluorescence transient parameters of leaf segments suggested no change in the F v/F m value due to UV-B or UV-B/A exclusion. Only a small reduction in photo-oxidized signal I (P700+)/unit Chl was noted. Interestingly the total soluble protein content per unit leaf area increased by 18% in UV-B/A and 40% in UV-B excluded samples, suggesting a unique upregulation of biosynthesis and accumulation of biomass. Solar UV radiation thus seems to primarily affect the photomorphogenic regulatory system that leads to an enhanced growth of leaves and an enhanced rate of net photosynthesis in soybean, a crop plant of economic importance. The presence of ultra-violet components in sunlight seems to arrest carbon sequestration in plants.

Enhancement of root growth and nitrogen fixation in Trigonella by UV-exclusion from solar radiation.

Science.gov (United States)

Sharma, Sonika; Guruprasad, K N

2012-12-01

A field experiment was conducted to study the impact of solar UV on root growth and nitrogen fixation in Trigonella foenum-graecum. Plants were grown in iron mesh cages covered with polyester filters that could specifically cut off UV-B (280-315 nm) or UV-A + B (280-400 nm) part of the solar spectrum. The control plants were grown under a polythene filter transmissible to UV. Root biomass, number of nodules and nodule fresh weight were enhanced after exclusion of solar UV. Nitrogenase activity was significantly enhanced by 120% and 80% in the UV-B and UV-A + B excluded plants respectively. Along with nitrogenase there was concomitant increase in leghemoglobin and hemechrome content in the nodules after exclusion of solar UV. These components of sunlight limits nitrogen fixation and their elimination can enhance nitrogen fixation with agricultural advantages like reduction in the use of fertilizers. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Sensitivity of upper atmospheric emissions calculations to solar/stellar UV flux

Directory of Open Access Journals (Sweden)

Barthelemy Mathieu

2014-01-01

Full Text Available The solar UV (UltraViolet flux, especially the EUV (Extreme UltraViolet and FUV (Far UltraViolet components, is one of the main energetic inputs for planetary upper atmospheres. It drives various processes such as ionization, or dissociation which give rise to upper atmospheric emissions, especially in the UV and visible. These emissions are one of the main ways to investigate the upper atmospheres of planets. However, the uncertainties in the flux measurement or modeling can lead to biased estimates of fundamental atmospheric parameters, such as concentrations or temperatures in the atmospheres. We explore the various problems that can be identified regarding the uncertainties in solar/stellar UV flux by considering three examples. The worst case appears when the solar reflection component is dominant in the recorded spectrum as is seen for outer solar system measurements from HST (Hubble Space Telescope. We also show that the estimation of some particular line parameters (intensity and shape, especially Lyman α, is crucial, and that both total intensity and line profile are useful. In the case of exoplanets, the problem is quite critical since the UV flux of their parent stars is often very poorly known.

Five years of solar UV-radiation monitoring in Sweden

Energy Technology Data Exchange (ETDEWEB)

Josefsson, Weine

1996-10-01

A network of five stations measuring the solar UV-radiation has been operated for about five years. Data are presented as plotted time-series of monthly and yearly values for the sites. A general climatology can be deduced from these data. Daily and hourly maximum values are shown for each month as indicators of the potential extreme exposure levels. The large annual variation at high latitudes is easily seen in the data set. This illustrates the importance of the solar elevation on the level of the UV-irradiance. Influence of cloud variation and of larger changes in ozone is also detectable. A few examples of the daily variation also show the strong solar elevation dependence of the UV-irradiance. The quantity and unit of the UV-radiation in this presentation is CIE-weighted irradiance expressed as MED (minimum erythermal dose), where one MED equals 210 Jm{sup -2}. The values have been recomputed to refer to the international intercomparison of broad-band meters in Helsinki in 1995. In the following named WMO-STUK 1995 scale. As will be seen there are many sources of error and detailed studies are prevented by the large uncertainty connected with these data. Due to the short period of the record and the low accuracy no attempt to study trends is done. 6 refs, 27 figs, 4 tabs

Inhibitory effects of ambient levels of solar UV-A and UV-B radiation in growth of cv. New Red Fire lettuce

International Nuclear Information System (INIS)

Krizek, D.T.; Britz, S.J.; Mirecki, R.M.

1998-01-01

The influence of solar UV-A and UV-B radiation at Beltsville, MD, USA, on growth of Lactuca sativa L. (cv. New Red Fire lettuce) was examined during early summer of 1996 and 1997. Plants were grown from seed in plastic window boxes covered with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or tefzel (1996) or teflon (1997) to transmit UV-A and UV-B radiation. After 31-34 days, plants grown in the absence of solar UV-B radiation (polyester) had 63 and 57% greater fresh weight and dry weight of tops, respectively, and 57, 72 and 47% greater dry weight of leaves, stems and roots, respectively, as compared to those grown under ambient UV-B (tefzel or teflon). Plants protected from UV-A radiation as well (Llumar) showed an additional 43 and 35% increase, respectively, in fresh and dry weight of tops and a 33 and 33% increase, respectively, in dry weight of leaves and stems, but no difference in root biomass over those grown under polyester. Excluding ambient UV-B (polyester) significantly reduced the UV absorbance of leaf extracts at 270, 300 and 330 nm (presumptive flavonoids) and the concentration of anthocyantins at 550 nm as compared to those of leaf extract from plants grown under ambient UV-A and UV-B. Additional removal of ambient UV-A (Llumar) reduced the concentration of anthocyanins, but had no further effect on UV absorbance at 270, 300 or 330 nm. These findings provide evidence that UV-B radiation is more important than UV-A radiation for flavonoid induction in this red-pigmented lettuce cultivar. Although previous workers have obtained decreases in lettuce yield under enhanced UV-B, this is the first evidence for inhibitory effects of solar UV-A and UV-B radiation on lettuce growth. (au)

Inhibitory effects of ambient levels of solar UV-A and UV-B radiation in growth of cv. New Red Fire lettuce

Energy Technology Data Exchange (ETDEWEB)

Krizek, D.T.; Britz, S.J.; Mirecki, R.M. [Climate Stress Laboratory, Beltsville, MD (United States)

1998-05-01

The influence of solar UV-A and UV-B radiation at Beltsville, MD, USA, on growth of Lactuca sativa L. (cv. New Red Fire lettuce) was examined during early summer of 1996 and 1997. Plants were grown from seed in plastic window boxes covered with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or tefzel (1996) or teflon (1997) to transmit UV-A and UV-B radiation. After 31-34 days, plants grown in the absence of solar UV-B radiation (polyester) had 63 and 57% greater fresh weight and dry weight of tops, respectively, and 57, 72 and 47% greater dry weight of leaves, stems and roots, respectively, as compared to those grown under ambient UV-B (tefzel or teflon). Plants protected from UV-A radiation as well (Llumar) showed an additional 43 and 35% increase, respectively, in fresh and dry weight of tops and a 33 and 33% increase, respectively, in dry weight of leaves and stems, but no difference in root biomass over those grown under polyester. Excluding ambient UV-B (polyester) significantly reduced the UV absorbance of leaf extracts at 270, 300 and 330 nm (presumptive flavonoids) and the concentration of anthocyantins at 550 nm as compared to those of leaf extract from plants grown under ambient UV-A and UV-B. Additional removal of ambient UV-A (Llumar) reduced the concentration of anthocyanins, but had no further effect on UV absorbance at 270, 300 or 330 nm. These findings provide evidence that UV-B radiation is more important than UV-A radiation for flavonoid induction in this red-pigmented lettuce cultivar. Although previous workers have obtained decreases in lettuce yield under enhanced UV-B, this is the first evidence for inhibitory effects of solar UV-A and UV-B radiation on lettuce growth. (au) 34 refs.

Solar UV exposure among outdoor workers in Denmark measured with personal UV-B dosimeters

DEFF Research Database (Denmark)

Grandahl, Kasper; Mortensen, Ole Steen; Sherman, David Zim

2017-01-01

radiation exposure are needed to help resolve this problem. This can be done using personal ultraviolet radiation dosimeters. Methods: We consider technical and practical feasibility of measuring individual solar ultraviolet exposure at work and leisure in professions with different á priori temporal high......-level outdoor worktime, using aluminium gallium nitride (AlGaN) photodiode detector based personal UV-B dosimeters. Essential technical specifications including the spectral and angular responsivity of the dosimeters are described and pre-campaign dosimeter calibration applicability is verified. The scale...... with our specialist knowledge as occupational physicians. Conclusions: Large-scale use of personal UV-B dosimeters for measurement of solar ultraviolet radiation exposure at work and leisure in Denmark is indeed feasible from a technical and practical viewpoint. Samples of exposure data shown support...

Effects of Solar UV Radiation and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

Science.gov (United States)

Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions...

Erythemal solar UV measurement network in New Zealand

International Nuclear Information System (INIS)

Smith, G.J.

1993-01-01

Measured daily total erythemal doses for 1989, 1990 and 1991 were presented and the cloudless-sky daily dose at the autumn equinox was approximately 30-50% higher than at the spring equinox as a result of the seasonal variation in ozone levels. In addition a substantially lower spring equinox erythemal dose was observed in 1991, probably as a result of increased aerosols arising from the Pinatubo eruption. An asymmetry in the diurnal pattern of irradiances about solar noon has been observed on cloudless days. Higher UV irradiances have been usually observed in the afternoons than in the mornings. Measurement of erythemal radiation is needed for skin cancer epidemiology projects. Given the uncertainties relating to the exposure of individuals to solar erythemal radiation, personal dosimeters may be very useful in providing more reliable personal UV exposure data. (author). 4 refs

Modeling the natural UV irradiation and comparative UV measurements at Moussala BEO (BG)

Science.gov (United States)

Tyutyundzhiev, N.; Angelov, Ch; Lovchinov, K.; Nitchev, Hr; Petrov, M.; Arsov, T.

2018-03-01

Studies of and modeling the impact of natural UV irradiation on the human population are of significant importance for human activity and economics. The sharp increase of environmental problems – extraordinary temperature changes, solar irradiation abnormalities, icy rains – raises the question of developing novel means of assessing and predicting potential UV effects. In this paper, we discuss new UV irradiation modeling based on recent real-time measurements at Moussala Basic Environmental Observatory (BEO) on Moussala Peak (2925 m ASL) in Rila Mountain, Bulgaria, and highlight the development and initial validation of portable embedded devices for UV-A, UV-B monitoring using open-source software architecture, narrow bandpass UV sensors, and the popular Arduino controllers. Despite the high temporal resolution of the VIS and UV irradiation measurements, the results obtained reveal the need of new assumptions in order to minimize the discrepancy with available databases.

Growth, photosynthesis and nitrogen metabolism in soybean varieties after exclusion of the UV-B and UV-A/B components of solar radiation

Directory of Open Access Journals (Sweden)

Sanjay Singh Baroniya

2014-12-01

Full Text Available A field experiment was conducted to study the impact of the exclusion of the solar UV components on growth, photosynthesis and nitrogen metabolism in soybean (Glycine max varieties PK-472, Pusa-24, JS 71-05, JS-335, NRC-7 and Kalitur. The plants were grown in specially designed UV exclusion chambers wrapped with filters to exclude UV-B or UV-A/B and transmitted all UV. Exclusion of UV significantly enhanced the growth of the aerial parts as well as the growth of the below ground parts in all of the six soybean varieties. Nitrate reductase activity (NRA was significantly reduced, whereas leghemoglobin (Lb content, total soluble protein, net photosynthesis (Pn and α-tocopherol content were enhanced after UV exclusion. The exclusion of solar UV-A/B enhanced all parameters to a larger extent than the exclusion of solar UV-B in four of the six varieties of soybean except for NRC-7 and Kalitur. These two varieties responded more to UV-B exclusion compared to UV-A/B exclusion. A significant inverse correlation between the NRA and the number of nodules per plant was observed. The extent of response in all parameters was greater in PK-472 and JS71-05 than that in Kalitur and JS-335 after UV exclusion. The exclusion of UV augmented the growth of nodules, Lb content and α-tocopherol levels and conferred higher rates of Pn to support better growth of nodules. Control plants (+ UV-A/B seemed to fulfill their N demand through the assimilation of NO3− resulting in lower symbiotic nitrogen fixation and higher NR activity.

Solar-Iss a New Solar Reference Spectrum Covering the Far UV to the Infrared (165 to 3088 Nm) Based on Reanalyzed Solar/solspec Cycle 24 Observations

Science.gov (United States)

Damé, L.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Bekki, S.; Bolsée, D.; Pereira, N.; Sluse, D.; Cessateur, G.

2017-12-01

Since April 5, 2008 and until February 15, 2017, the SOLSPEC (SOLar SPECtrometer) spectro-radiometer of the SOLAR facility on the International Space Station performed accurate measurements of Solar Spectral Irradiance (SSI) from the far ultraviolet to the infrared (165 nm to 3088 nm). These measurements, unique by their large spectral coverage and long time range, are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry), noticeably through the "top-down" mechanism amplifying ultraviolet (UV) solar forcing effects on the climate (UV affects stratospheric dynamics and temperatures, altering interplanetary waves and weather patterns both poleward and downward to the lower stratosphere and troposphere regions). SOLAR/SOLSPEC, with almost 9 years of observations covering the essential of the unusual solar cycle 24 from minimum in 2008 to maximum, allowed to establish new reference solar spectra from UV to IR (165 to 3088 nm) at minimum (beginning of mission) and maximum of activity. The complete reanalysis was possible thanks to revised engineering corrections, improved calibrations and advanced procedures to account for thermal, aging and pointing corrections. The high quality and sensitivity of SOLSPEC data allow to follow temporal variability in UV but also in visible along the cycle. Uncertainties on these measurements are evaluated and results, absolute reference spectra and variability, are compared with other measurements (WHI, ATLAS-3, SCIAMACHY, SORCE/SOLSTICE, SORCE/SIM) and models (SATIRE-S, NRLSSI, NESSY)

The research on a novel type of the solar-blind UV head-mounted displays

Science.gov (United States)

Zhao, Shun-long

2011-08-01

Ultraviolet technology of detecting is playing a more and more important role in the field of civil application, especially in the corona discharge detection, in modern society. Now the UV imaging detector is one of the most important equipments in power equipment flaws detection. And the modern head-mounted displays (HMDs) have shown the applications in the fields of military, industry production, medical treatment, entertainment, 3D visualization, education and training. We applied the system of head-mounted displays to the UV image detection, and a novel type of head-mounted displays is presented: the solar-blind UV head-mounted displays. And the structure is given. By the solar-blind UV head-mounted displays, a real-time, isometric and visible image of the corona discharge is correctly displayed upon the background scene where it exists. The user will see the visible image of the corona discharge on the real scene rather than on a small screen. Then the user can easily find out the power equipment flaws and repair them. Compared with the traditional UV imaging detector, the introducing of the HMDs simplifies the structure of the whole system. The original visible spectrum optical system is replaced by the eye in the solar-blind UV head-mounted displays. And the optical image fusion technology would be used rather than the digital image fusion system which is necessary in traditional UV imaging detector. That means the visible spectrum optical system and digital image fusion system are not necessary. This makes the whole system cheaper than the traditional UV imaging detector. Another advantage of the solar-blind UV head-mounted displays is that the two hands of user will be free. So while observing the corona discharge the user can do some things about it. Therefore the solar-blind UV head-mounted displays can make the corona discharge expose itself to the user in a better way, and it will play an important role in corona detection in the future.

MEDICAL AND ENVIRONMENTAL EFFECTS OF UV RADIATION.

Energy Technology Data Exchange (ETDEWEB)

SUTHERLAND, B.M.

2001-07-26

Organisms living on the earth are exposed to solar radiation, including its ultraviolet (UV) components (for general reviews, the reader is referred to Smith [1] and Young et al. [2]). UV wavelength regions present in sunlight are frequently designated as UVB (290-320 nm) and UVA (320-400 nm). In today's solar spectrum, UVA is the principal UV component, with UVB present at much lower levels. Ozone depletion will increase the levels of UVB reaching the biosphere, but the levels of UVA will not be changed significantly [3]. Because of the high efficiency of UVB in producing damage in biological organisms in the laboratory experiments, it has sometimes been assumed that UVA has little or no adverse biological effects. However, accumulating data [4, 5], including action spectra (efficiency of biological damage as a function of wavelength of radiation; see Section 5) for DNA damage in alfalfa seedlings [6], in human skin [7], and for a variety of plant damages (Caldwell, this volume) indicate that UVA can induce damage in DNA in higher organisms. Thus, understanding the differential effects of UVA and UVB wavebands is essential for estimating the biological consequences of stratospheric ozone depletion.

Combined impact of solar UV-B radiation and selenium treatment on respiratory potential in pumpkins (Cucurbita pepo L.)

International Nuclear Information System (INIS)

Germ, M.

2005-01-01

The effects of ambient and filtered solar UV-B radiation and of selenium treatment on respiratory potential measured by electron transport system (ETS) activity in pumpkins, Cucurbita pepo L. were studied. Measurements were conducted three times in the growth period. Solar UV-B radiation decreased ETS activity in plants, regardless selenium treatment. The results suggested that the solar UV-B radiation impaired flow of electrons in the respiratory chain. Selenium decreased ETS activity in plants exposed to solar UV-B radiation in the end of the vegetation period

Solar Coronal UV Spectroscopy for Solar Wind and SEP Acceleration Investigations

Science.gov (United States)

Moses, John Daniel; Ko, Yuan-Kuen; Laming, John Martin; Strachan, Leonard; Tun Beltran, Samuel

2015-04-01

Of all the new areas of solar physics opened by the landmark SOHO mission, the scientific discoveries of the Ultraviolet Coronagraph Spectrometer (UVCS) are unique in both the importance of the new questions raised by these observations and the lack of subsequent investigations to resolve these questions. For example, the first direct evidence of wave-particle coupling as an acceleration mechanism for the solar wind was obtained from UVCS spectro-coronagraphic observations, yet the real limits on the ratio of the parallel to perpendicular ion temperatures (with respect to the magnetic field) in coronal holes and streamers is still unresolved. Another unresolved issue is the role of suprathermal seed particles in rapid diffusive shock acceleration of SEPs. Although the theory has been placed on firmer theoretical ground by recent in situ investigations, observations of these suprathermal particles in the corona was never conclusively obtained with UVCS.Any follow-on UV Spectro-coronagraph must possess two improvements over UVCS in order to address the questions raised during the SOHO mission: 1) increased effective aperture and 2) improved spectrographic contrast (i.e. reduced scattered light). Technological developments in optics, optical design, UV detectors, composite structures, cleanliness control and electronics make it possible to achieve the requisite improvements in a next-generation UV spectro-coronagraph within the constraints of an affordable mission. We discuss specific instrument and mission approaches developed over the last 5 years and the feasibility of implementing them within the next 5 years.

Environmental testing of flat plate solar cell modules

Science.gov (United States)

Griffith, J.; Dumas, L.; Hoffman, A.

1978-01-01

Commercially available flat-plate solar cell modules have been subjected to a variety of environmental tests designed to simulate service conditions. Among the tests are those simulating heat and rain, wind-driven rains, humidity and freezing, humidity and heat, humidity with a voltage bias, salt fog, hail impact, and fungus infestation. Tests for optical surface soiling and the combined effects of temperature, humidity and UV irradiation are under development. A correlation has been demonstrated between degradation caused by the qualification tests and such observed field effects as power loss.

Single Photon Counting UV Solar-Blind Detectors Using Silicon and III-Nitride Materials

Science.gov (United States)

Nikzad, Shouleh; Hoenk, Michael; Jewell, April D.; Hennessy, John J.; Carver, Alexander G.; Jones, Todd J.; Goodsall, Timothy M.; Hamden, Erika T.; Suvarna, Puneet; Bulmer, J.; Shahedipour-Sandvik, F.; Charbon, Edoardo; Padmanabhan, Preethi; Hancock, Bruce; Bell, L. Douglas

2016-01-01

Ultraviolet (UV) studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR) and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE) measurements show QE > 50% in the 100–300 nm range for detectors with simple AR coatings, and QE ≅ 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness. PMID:27338399

The Nrf2-inducers tanshinone I and dihydrotanshinone protect human skin cells and reconstructed human skin against solar simulated UV.

Science.gov (United States)

Tao, Shasha; Justiniano, Rebecca; Zhang, Donna D; Wondrak, Georg T

2013-01-01

Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photocarcinogenesis and photoaging, and an urgent need exists for improved strategies for skin photoprotection. The redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2), a master regulator of the cellular antioxidant defense against environmental electrophilic insult, has recently emerged as an important determinant of cutaneous damage from solar UV, and the concept of pharmacological activation of Nrf2 has attracted considerable attention as a novel approach to skin photoprotection. In this study, we examined feasibility of using tanshinones, a novel class of phenanthrenequinone-based cytoprotective Nrf2 inducers derived from the medicinal plant Salvia miltiorrhiza, for protection of cultured human skin cells and reconstructed human skin against solar simulated UV. Using a dual luciferase reporter assay in human Hs27 dermal fibroblasts pronounced transcriptional activation of Nrf2 by four major tanshinones [tanshinone I (T-I), dihydrotanshinone (DHT), tanshinone IIA (T-II-A) and cryptotanshinone (CT)] was detected. In fibroblasts, the more potent tanshinones T-I and DHT caused a significant increase in Nrf2 protein half-life via blockage of ubiquitination, ultimately resulting in upregulated expression of cytoprotective Nrf2 target genes (GCLC, NQO1) with the elevation of cellular glutathione levels. Similar tanshinone-induced changes were also observed in HaCaT keratinocytes. T-I and DHT pretreatment caused significant suppression of skin cell death induced by solar simulated UV and riboflavin-sensitized UVA. Moreover, feasibility of tanshinone-based cutaneous photoprotection was tested employing a human skin reconstruct exposed to solar simulated UV (80 mJ/cm(2) UVB; 1.53 J/cm(2) UVA). The occurrence of markers of epidermal solar insult (cleaved procaspase 3, pycnotic nuclei, eosinophilic cytoplasm, acellular cavities) was significantly attenuated in DHT

The Nrf2-inducers tanshinone I and dihydrotanshinone protect human skin cells and reconstructed human skin against solar simulated UV

Directory of Open Access Journals (Sweden)

Shasha Tao

2013-01-01

Full Text Available Exposure to solar ultraviolet (UV radiation is a causative factor in skin photocarcinogenesis and photoaging, and an urgent need exists for improved strategies for skin photoprotection. The redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2, a master regulator of the cellular antioxidant defense against environmental electrophilic insult, has recently emerged as an important determinant of cutaneous damage from solar UV, and the concept of pharmacological activation of Nrf2 has attracted considerable attention as a novel approach to skin photoprotection. In this study, we examined feasibility of using tanshinones, a novel class of phenanthrenequinone-based cytoprotective Nrf2 inducers derived from the medicinal plant Salvia miltiorrhiza, for protection of cultured human skin cells and reconstructed human skin against solar simulated UV. Using a dual luciferase reporter assay in human Hs27 dermal fibroblasts pronounced transcriptional activation of Nrf2 by four major tanshinones [tanshinone I (T-I, dihydrotanshinone (DHT, tanshinone IIA (T-II-A and cryptotanshinone (CT] was detected. In fibroblasts, the more potent tanshinones T-I and DHT caused a significant increase in Nrf2 protein half-life via blockage of ubiquitination, ultimately resulting in upregulated expression of cytoprotective Nrf2 target genes (GCLC, NQO1 with the elevation of cellular glutathione levels. Similar tanshinone-induced changes were also observed in HaCaT keratinocytes. T-I and DHT pretreatment caused significant suppression of skin cell death induced by solar simulated UV and riboflavin-sensitized UVA. Moreover, feasibility of tanshinone-based cutaneous photoprotection was tested employing a human skin reconstruct exposed to solar simulated UV (80 mJ/cm2 UVB; 1.53 J/cm2 UVA. The occurrence of markers of epidermal solar insult (cleaved procaspase 3, pycnotic nuclei, eosinophilic cytoplasm, acellular cavities was significantly attenuated in DHT

Photosynthetic Performance of the Red Alga Pyropia haitanensis During Emersion, With Special Reference to Effects of Solar UV Radiation, Dehydration and Elevated CO2 Concentration.

Science.gov (United States)

Xu, Juntian; Gao, Kunshan

2015-11-01

Macroalgae distributed in intertidal zones experience a series of environmental changes, such as periodical desiccation associated with tidal cycles, increasing CO2 concentration and solar UVB (280-315 nm) irradiance in the context of climate change. We investigated how the economic red macroalga, Pyropia haitanensis, perform its photosynthesis under elevated atmospheric CO2 concentration and in the presence of solar UV radiation (280-400 nm) during emersion. Our results showed that the elevated CO2 (800 ppmv) significantly increased the photosynthetic carbon fixation rate of P. haitanensis by about 100% when the alga was dehydrated. Solar UV radiation had insignificant effects on the net photosynthesis without desiccation stress and under low levels of sunlight, but significantly inhibited it with increased levels of desiccation and sunlight intensity, to the highest extent at the highest levels of water loss and solar radiation. Presence of UV radiation and the elevated CO2 acted synergistically to cause higher inhibition of the photosynthetic carbon fixation, which exacerbated at higher levels of desiccation and sunlight. While P. haitanensis can benefit from increasing atmospheric CO2 concentration during emersion under low and moderate levels of solar radiation, combined effects of elevated CO2 and UV radiation acted synergistically to reduce its photosynthesis under high solar radiation levels during noon periods. © 2015 The American Society of Photobiology.

UV radiation: sources, effects and risks of human and environmental exposure

International Nuclear Information System (INIS)

Eggink, G.J.; Slaper, H.

1992-01-01

This paper summarizes the principal results of a review study on UV- -exposure and UV related risks in the Netherlands. Both the present state of affairs and future developments are discussed, the latter partly based on model calculations. The sun is the main UV source to which the whole population is exposed. Solar exposure is estimated to amount at least 90% of the annual UV burden for the Dutch population. For certain groups in the population man made sources are estimated to contribute considerably to the yearly UV dose. Ozone depletion as a result of human activities, growing use of tungsten halogen lamps and increasing application of UV-sources in industry and medicine all tend to increase UV exposure. UV exposure can lead to a wide variety of health effects, among which the induction of skin cancer, skin aging, cataract formation and suppression of immune responses. Risk estimates of these health effects are available for skin cancer and to a lesser extend for cataracts. The estimated UV related skin cancer incidence rate in the Netherlands is 10 -3 per year (15 000 cases), and the associated mortality rate amounts to 6-25·10 -6 per year (90-400 deaths). The ozone depletion presently observed over the past decade (5% in the Netherlands), is expected to lead to an increased annual mortality rate due to skin cancer of 1,3·10 -6 per year. Environmental exposure can influence plant physiology and lead to a decrease of biomass in aquatic as well as terrestrial ecosystems. This may result in adverse effects on the foodweb and biodiversity of ecosystems. Quantitative risk estimates for these effects are very uncertain or lacking. (author)

Assessment of integrated solar ultraviolet radiation by PM-355 detectors

International Nuclear Information System (INIS)

Abu-Jarad, F.; Al-Jarallah, M.I.; Elhadidy, M.A.; Shaahid, S.M.; Fazal-ur-Rehman

2000-01-01

The increase in environmental solar UV radiation due to depletion of ozone layer is a recent challenge to human health (skin cancer and eye effects) in countries having clear skies. Therefore, applying integrated, passive and inexpensive techniques to assess solar UV radiation is very much essential. Measurements of environmental solar UV radiation in Dhahran, Saudi Arabia area were carried out for a period of two months in the summer period in 1996 using two techniques in parallel namely: passive nuclear track detectors and active solar UV radiometers. Some of the nuclear track detectors were mounted in different conditions such as: under shadow band, on solar tracking mechanism following the solar rays. Others were mounted on perpendicular, tilted and horizontal surfaces in sunlight. All detectors were attached to a wooden background of the same thickness (0.5 cm) to eliminate interference of the heat effect of various support materials and have uniformity of the support materials. The assessment was carried out for different periods extending from two to nine weeks continuously. The investigated period covered the hottest months in Saudi Arabia (July and August) when the sky was clear of clouds. The results indicate linear correlation between alpha track diameters and the integrated exposure to solar UV as measured by the solar UV radiometer for all nuclear track detector positions and orientations. The highest slope has been observed for the detectors placed on solar tracking mechanism following the solar rays and the lowest from detectors oriented under the shadow band on horizontal position (measuring the diffused UV radiation only). The results show that most of the measured UV radiation (60%) were from the diffused UV radiation. The characteristics of the upper layer of the detectors are changed after chemical etching very quickly, with increase in the exposure time to UV solar radiation at certain orientation. The results encourage the use of nuclear track

Assessment of integrated solar ultraviolet radiation by PM-355 detectors

Energy Technology Data Exchange (ETDEWEB)

Abu-Jarad, F.; Al-Jarallah, M.I.; Elhadidy, M.A.; Shaahid, S.M.; Fazal-ur-Rehman

2000-06-01

The increase in environmental solar UV radiation due to depletion of ozone layer is a recent challenge to human health (skin cancer and eye effects) in countries having clear skies. Therefore, applying integrated, passive and inexpensive techniques to assess solar UV radiation is very much essential. Measurements of environmental solar UV radiation in Dhahran, Saudi Arabia area were carried out for a period of two months in the summer period in 1996 using two techniques in parallel namely: passive nuclear track detectors and active solar UV radiometers. Some of the nuclear track detectors were mounted in different conditions such as: under shadow band, on solar tracking mechanism following the solar rays. Others were mounted on perpendicular, tilted and horizontal surfaces in sunlight. All detectors were attached to a wooden background of the same thickness (0.5 cm) to eliminate interference of the heat effect of various support materials and have uniformity of the support materials. The assessment was carried out for different periods extending from two to nine weeks continuously. The investigated period covered the hottest months in Saudi Arabia (July and August) when the sky was clear of clouds. The results indicate linear correlation between alpha track diameters and the integrated exposure to solar UV as measured by the solar UV radiometer for all nuclear track detector positions and orientations. The highest slope has been observed for the detectors placed on solar tracking mechanism following the solar rays and the lowest from detectors oriented under the shadow band on horizontal position (measuring the diffused UV radiation only). The results show that most of the measured UV radiation (60%) were from the diffused UV radiation. The characteristics of the upper layer of the detectors are changed after chemical etching very quickly, with increase in the exposure time to UV solar radiation at certain orientation. The results encourage the use of nuclear track

Photocatalytic degradation and mineralization of microcystin-LR under UV-A, solar and visible light using nanostructured nitrogen doped TiO2

International Nuclear Information System (INIS)

Triantis, T.M.; Fotiou, T.; Kaloudis, T.; Kontos, A.G.; Falaras, P.; Dionysiou, D.D.; Pelaez, M.; Hiskia, A.

2012-01-01

Highlights: ► N-TiO 2 exhibited effective degradation of MC-LR under UV-A, solar and visible light. ► Complete photocatalytic mineralization of MC-LR was achieved under UV-A and solar light. ► The organic nitrogen is mainly released as ammonium and nitrate ions. - Abstract: In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO 2 (N-TiO 2 ) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO 2 , Kronos and reference TiO 2 nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO 2 followed by N-TiO 2 with 96% toxin destruction after 20 min of illumination. Under solar light illumination, N-TiO 2 nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO 2 for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO 2 displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO 2 − , NO 3 − and NH 4 + ) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light.

Calibration of the solar UV radiometers in Finland

Energy Technology Data Exchange (ETDEWEB)

Leszczynski, K; Jokela, K; Visuri, R; Ylianttila, L [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland). Non-Ionizing Radiation Lab.

1997-12-31

In this report, the main emphasis is given to (1) the problems associated with the basic calibration of the spectroradiometer and (2) the year-to-year variability of the calibrations of the solar UV network radiometers. Also, the results from intercomparisons of the Brewer and OL 742 spectroradiometers are included

Calibration of the solar UV radiometers in Finland

Energy Technology Data Exchange (ETDEWEB)

Leszczynski, K.; Jokela, K.; Visuri, R.; Ylianttila, L. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland). Non-Ionizing Radiation Lab.

1996-12-31

In this report, the main emphasis is given to (1) the problems associated with the basic calibration of the spectroradiometer and (2) the year-to-year variability of the calibrations of the solar UV network radiometers. Also, the results from intercomparisons of the Brewer and OL 742 spectroradiometers are included

Induction of UV photoproducts and DNA damage by solar simulator UV irradiation

International Nuclear Information System (INIS)

Wolfreys, A.; Henderson, L.; Clingen, P.

1997-01-01

The recent increased incidence of skin cancer and the depletion of the ozone layer has increased interest in the ultraviolet (UV) component of natural sunlight and its role in the induction of skin cancer. Previous research on UV radiation has concentrated on UVC (254nm) but, as only UVB and UVA are present in natural sunlight, its relevance is unknown. We have investigated the induction of two forms of direct DNA damage - the pyrimidine dimer and the (6-4) photoproduct - in human DNA repair deficient XP-G (Xeroderma pigmentosum group G) lymphoblastoid cells following exposure to simulated sunlight. As exposure to natural sunlight is highly variable, a solar simulator lamp was used which is known to mimic natural sunlight at midday in Central Europe. Cells were irradiated on ice to minimise DNA repair and the relative induction of pyrimidine dimers and (6-4) photoproducts was measured using specific monoclonal antibodies and a computer assisted image analysis system. A time dependent increase in both cyclobutane dimer and (6-4) photoproduct antibody binding sites was seen. The increases in pyrimidine dimer and (6-4) photoproduct antibody binding sites differed to that reported with natural sunlight in the UK but was similar to that seen with a similar solar simulator lamp

New down-converter for UV-stable perovskite solar cells: Phosphor-in-glass

Science.gov (United States)

Roh, Hee-Suk; Han, Gill Sang; Lee, Seongha; Kim, Sanghyun; Choi, Sungwoo; Yoon, Chulsoo; Lee, Jung-Kun

2018-06-01

Degradation of hybrid lead halide perovskite by UV light is a crucial issue that limits the commercialization of lead halide perovskite solar cells (PSCs). To address this problem, phosphor-in-glass (PiG) is used to convert UV to visible light. Down-conversion of UV light by PiG dramatically increases UV-stability of PSCs and enables PSCs to harvest UV light that is currently wasted. Performance of PSCs with PiG layer does not change significantly during 100 h-long UV-irradiation, while conventional PSCs degrade quickly by 1 h-long UV-irradiation. After 100 h long UV-irradiation, power conversion efficiency of PSCs with PiG is 440% larger than that of conventional PSCs. This result points a direction toward PSCs which are very stable and highly efficient under UV light.

Photocatalytic degradation and mineralization of microcystin-LR under UV-A, solar and visible light using nanostructured nitrogen doped TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Triantis, T.M.; Fotiou, T. [Laboratory of Catalytic - Photocatalytic Processes (Solar Energy - Environment), Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece); Kaloudis, T. [Organic Micropollutants Laboratory, Athens Water Supply and Sewerage Company (EYDAP SA), WTP Aharnon, Menidi (Greece); Kontos, A.G.; Falaras, P. [Laboratory of Photo-redox Conversion and Storage of Solar Energy, Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece); Dionysiou, D.D.; Pelaez, M. [Environmental Engineering and Science Program, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, OH 45221-0012 (United States); Hiskia, A., E-mail: hiskia@chem.demokritos.gr [Laboratory of Catalytic - Photocatalytic Processes (Solar Energy - Environment), Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece)

2012-04-15

Highlights: Black-Right-Pointing-Pointer N-TiO{sub 2} exhibited effective degradation of MC-LR under UV-A, solar and visible light. Black-Right-Pointing-Pointer Complete photocatalytic mineralization of MC-LR was achieved under UV-A and solar light. Black-Right-Pointing-Pointer The organic nitrogen is mainly released as ammonium and nitrate ions. - Abstract: In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO{sub 2} (N-TiO{sub 2}) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO{sub 2}, Kronos and reference TiO{sub 2} nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO{sub 2} followed by N-TiO{sub 2} with 96% toxin destruction after 20 min of illumination. Under solar light illumination, N-TiO{sub 2} nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO{sub 2} for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO{sub 2} displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO{sub 2}{sup -}, NO{sub 3}{sup -} and NH{sub 4}{sup +}) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light.

Solar UV-B radiation modulates chemical defenses against Anticarsia gemmatalis larvae in leaves of field-grown soybean.

Science.gov (United States)

Dillon, Francisco M; Chludil, Hugo D; Zavala, Jorge A

2017-09-01

Although it is well known that solar ultraviolet B (UV-B) radiation enhances plant defenses, there is less knowledge about traits that define insect resistance in field-grown soybean. Here we study the effects of solar UV-B radiation on: a) the induction of phenolic compounds and trypsin proteinase inhibitors (TPI) in soybean undamaged leaves or damaged by Anticarsia gemmatalis neonates during six days, and b) the survival and mass gain of A. gemmatalis larvae that fed on soybean foliage. Two soybean cultivars (cv.), Charata and Williams, were grown under plastic with different transmittance to solar UV-B radiation, which generated two treatments: ambient UV-B (UVB+) and reduced UV-B (UVB-) radiation. Solar UV-B radiation decreased survivorship by 30% and mass gain by 45% of larvae that fed on cv. Charata, but no effect was found in those larvae that fed on cv. Williams. TPI activity and malonyl genistin were induced by A. gemmatalis damage in both cultivars, but solar UV-B radiation and damage only synergistically increased the induction of these compounds in cv. Williams. Although TPI activity and genistein derivatives were induced by herbivory, these results did not explain the differences found in survivorship and mass gain of larvae that fed on cv. Charata. However, we found a positive association between lower larval performance and the presence of two quercetin triglycosides and a kaempferol triglycoside in foliage of cv. Charata, which were identified by HPLC-DAD/MS 2 . We conclude that exclusion of solar UV-B radiation reduce resistance to A. gemmatalis, due to a reduction in flavonol concentration in a cultivar that has low levels of genistein derivatives like cv. Charata. Copyright © 2017 Elsevier Ltd. All rights reserved.

Growth, photosynthesis and nitrogen metabolism in soybean varieties after exclusion of the UV-B and UV-A/B components of solar radiation

OpenAIRE

Sanjay Singh Baroniya; Sunita Kataria; Govind Prakash Pandey; Kadur N. Guruprasad

2014-01-01

A field experiment was conducted to study the impact of the exclusion of the solar UV components on growth, photosynthesis and nitrogen metabolism in soybean (Glycine max) varieties PK-472, Pusa-24, JS 71-05, JS-335, NRC-7 and Kalitur. The plants were grown in specially designed UV exclusion chambers wrapped with filters to exclude UV-B or UV-A/B and transmitted all UV. Exclusion of UV significantly enhanced the growth of the aerial parts as well as the growth of the below ground parts in all...

Relationship of photosynthetic carbon fixation with environmental changes in the Jiulong River estuary of the South China Sea, with special reference to the effects of solar UV radiation

International Nuclear Information System (INIS)

Li Gang; Gao Kunshan; Yuan Dongxing; Zheng Ying; Yang Guiyuan

2011-01-01

Highlights: → C-fixation is the highest in turbidity front, though UV resulted in higher inhibition. → Increased availability of CO 2 appeared to stimulate photosynthetic machinery. → Osmotic stress made phytoplankton more sensitive to UV. - Abstract: Phytoplankton cells in estuary waters usually experience drastic changes in chemical and physical environments due to mixing of fresh and seawaters. In order to see their photosynthetic performance in such dynamic waters, we measured the photosynthetic carbon fixation by natural phytoplankton assemblages in the Jiulong River estuary of the South China Sea during April 24-26 and July 24-26 of 2008, and investigated its relationship with environmental changes in the presence or the absence of UV radiation. Phytoplankton biomass (Chl a) decreased sharply from the river-mouth to seawards (17.3-2.1 μg L -1 ), with the dominant species changed from chlorophytes to diatoms. The photosynthetic rate based on Chl a at noon time under PAR-alone increased from 1.9 μg C (μg Chl a) -1 L -1 in low salinity zone (SSS -1 L -1 in turbidity front (SSS within 10-20), and then decreased to 2.1 μg C (μg Chl a) -1 L -1 in mixohaline zone (SSS > 20); accordingly, the carbon fixation per volume of seawater increased from 12.8 to 149 μg C L -1 h -1 , and decreased to 14.3 μg C L -1 h -1 . Solar UVR caused the inhibition of carbon fixation in surface water of all the investigated zones, by 39% in turbidity area and 7-10% in freshwater or mixohaline zones. In the turbidity zone, higher availability of CO 2 could have enhanced the photosynthetic performance; while osmotic stress might be responsible for the higher sensitivity of phytoplankton assemblages to solar UV radiation.

Ambient solar UV radiation and seasonal trends in potential sunburn ...

African Journals Online (AJOL)

Background. The detrimental effects of excess personal solar ultraviolet (UV) radiation exposure include sunburn, immunosuppression and skin cancer. In South Africa, individuals with minimum natural protection from melanin, including fair-skinned individuals and African albinos, and people spending extended ...

Malbec grape (Vitis vinifera L.) responses to the environment: Berry phenolics as influenced by solar UV-B, water deficit and sprayed abscisic acid.

Science.gov (United States)

Alonso, Rodrigo; Berli, Federico J; Fontana, Ariel; Piccoli, Patricia; Bottini, Rubén

2016-12-01

High-altitude vineyards receive elevated solar ultraviolet-B (UV-B) levels so producing high quality berries for winemaking because of induction in the synthesis of phenolic compounds. Water deficit (D) after veraison, is a commonly used tool to regulate berry polyphenols concentration in red wine cultivars. Abscisic acid (ABA) plays a crucial role in the acclimation to environmental factors/signals (including UV-B and D). The aim of the present study was to evaluate independent and interactive effects of high-altitude solar UV-B, moderate water deficit and ABA applications on Vitis vinifera cv. Malbec berries. The experiment was conducted during two growing seasons with two treatments of UV-B (+UV-B and -UV-B), watering (+D and -D) and ABA (+ABA and -ABA), in a factorial design. Berry fresh weight, sugar content, fruit yield, phenolic compounds profile and antioxidant capacity (ORAC) were analyzed at harvest. Previous incidence of high UV-B prevented deleterious effects of water deficit, i.e. berry weight reduction and diminution of sugar accumulation. High UV-B increased total phenols (mainly astilbin, quercetin and kaempferol) and ORAC, irrespectively of the combination with other factors. Fruit yield was reduced by combining water deficit and high UV-B or water deficit and ABA. Two applications of ABA were enough to induced biochemical changes increasing total anthocyanins, especially those with higher antioxidant capacity. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

CuS/RGO hybrid photocatalyst for full solar spectrum photoreduction from UV/Vis to near-infrared light.

Science.gov (United States)

Wu, Jie; Liu, Baibai; Ren, Zhenxing; Ni, Mengying; Li, Can; Gong, Yinyan; Qin, Wei; Huang, Yongli; Sun, Chang Q; Liu, Xinjuan

2018-05-01

To make full use of the solar energy, it remains a great challenge for semiconductor photocatalysts to harvest the full solar light spectrum from ultraviolet (UV) to visible even the near infrared (NIR) wavelength. Here we show firstly the CuS/RGO (reduced graphene oxide) hybrid photocatalyst synthesized via a microwave assisted method with full solar light (UV-Vis-NIR) active for efficient Cr(VI) reduction. The CuS/RGO displays high absorption and catalytic activity in the UV, visible and even the NIR light regions. As co-catalyst, RGO can separate and inhibit the recombination of charge carriers, consequently improving the catalytic activity. Only 1wt% RGO emersions can reduce 90% of Cr(VI) under the radiation of light over the full spectrum. Findings may provide a new strategy and substance to expand the utilization range of solar light from UV to visible even the NIR energy. Copyright © 2017. Published by Elsevier Inc.

Design progress of the solar UV-Vis-IR telescope (SUVIT) aboard SOLAR-C

Science.gov (United States)

Katsukawa, Y.; Ichimoto, K.; Suematsu, Y.; Hara, H.; Kano, R.; Shimizu, T.; Matsuzaki, K.

2013-09-01

We present a design progress of the Solar UV-Vis-IR Telescope (SUVIT) aboard the next Japanese solar mission SOLAR-C. SUVIT has an aperture diameter of ~1.4 m for achieving spectro-polarimetric observations with spatial and temporal resolution exceeding the Hinode Solar Optical Telescope (SOT). We have studied structural and thermal designs of the optical telescope as well as the optical interface between the telescope and the focal plane instruments. The focal plane instruments are installed into two packages, filtergraph and spectrograph packages. The spectropolarimeter is the instrument dedicated to accurate polarimetry in the three spectrum windows at 525 nm, 854 nm, and 1083 nm for observing magnetic fields at both the photospheric and chromospheric layers. We made optical design of the spectrograph accommodating the conventional slit spectrograph and the integral field unit (IFU) for two-dimensional coverage. We are running feasibility study of the IFU using fiber arrays consisting of rectangular cores.

Reconstruction of solar spectral surface UV irradiances using radiative transfer simulations.

Science.gov (United States)

Lindfors, Anders; Heikkilä, Anu; Kaurola, Jussi; Koskela, Tapani; Lakkala, Kaisa

2009-01-01

UV radiation exerts several effects concerning life on Earth, and spectral information on the prevailing UV radiation conditions is needed in order to study each of these effects. In this paper, we present a method for reconstruction of solar spectral UV irradiances at the Earth's surface. The method, which is a further development of an earlier published method for reconstruction of erythemally weighted UV, relies on radiative transfer simulations, and takes as input (1) the effective cloud optical depth as inferred from pyranometer measurements of global radiation (300-3000 nm); (2) the total ozone column; (3) the surface albedo as estimated from measurements of snow depth; (4) the total water vapor column; and (5) the altitude of the location. Reconstructed daily cumulative spectral irradiances at Jokioinen and Sodankylä in Finland are, in general, in good agreement with measurements. The mean percentage difference, for instance, is mostly within +/-8%, and the root mean square of the percentage difference is around 10% or below for wavelengths over 310 nm and daily minimum solar zenith angles (SZA) less than 70 degrees . In this study, we used pseudospherical radiative transfer simulations, which were shown to improve the performance of our method under large SZA (low Sun).

Effects of solar and artificial UV irradiation on motility and phototaxis in the flagellate, Euglena gracilis

International Nuclear Information System (INIS)

Haeder, D.-P.

1986-01-01

The effect of solar irradiation on the percentage of motile cells, their average speed and their phototactic orientation to white actinic light was studied in the flagellate, Euglena gracilis. Unfiltered solar radiation in midsummer during mid-day at a location near Lisboa, Portugal, was found to impair motility within 2 h. This effect is exclusively due to the UV-B component of the radiation and not due to UV-A, visible light or a temperature increase. Likewise, phototactic orientation was drastically impaired. Reduction of the solar UV-B irradiation by insertion of an ozone-flooded plexiglass cuvette partially reduced the inhibition and covering the cuvettes with glass prevented any decrease in motility and photoorientation. Similar results were found with artificial irradiation (Xe lamps). After inoculation, the motility of the population follows an optimum curve (optimum at 8 days). Also, the UV-B effect on motility was smallest after about one week and increased for younger and older cultures. (author)

Inhibition of motility in the cyanobacterium, Phormidium uncinatum, by solar and monochromatic UV irradiation

International Nuclear Information System (INIS)

Häder, D.P.; Watanabe, M.; Furuya, M.

1986-01-01

The effect of solar radiation and monochromatic UV radiation on the motility of the filamentous cyanobacterium Phormidium uncinatum was determined. Solar radiation (mid-day, in midsummer at a location near Lisboa, Portugal) was found to impair motility within about 30 min. This effect is neither a result of a temperature increase nor of visible light. The spectral sensitivity determined using the Okazaki Largé Spectrograph shows the maximal effectiveness of radiation of ≤300 nm. The short time requirement for the response and the lack of any photoreactivation of motility argues against DNA being the UV target. Investigations using reagents diagnostic of superoxide free radicals and singlet oxygen failed to confirm the involvement of photodynamic effects as the molecular mechanism causing UV inhibition of motility

Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

Science.gov (United States)

Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

2008-06-01

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, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

The Global Solar UV Index used in the United Kingdom

International Nuclear Information System (INIS)

New, C.; Driscoll, C.M.H.; Kitchen, K.; Miners, B.

2000-01-01

Weather forecast bulletins on television, radio and in the newspapers in the UK now include advice about the strength of the ultraviolet (UV) radiation from the sun in terms of the Global Solar UV Index. A numerical scale of 1 to 20 is used to quote the Index for anywhere in the world and the Index addresses all ethnic groups. The Index replaces the sunburn warning system. The daily UV Index is calculated by the Met. Office from documented UV radiation levels and current atmospheric data and takes into account cloud cover forecast. Armed with the knowledge of the UV Index the public will be able to assess their personal risk of sun damage at home or abroad depending on their natural skin colour. Four categories of skin colour are identified with the Index; white skin that sunburns easily, white skin that tans readily, brown skin and black skin. A colour-coded rating from low to very high is used to identify personal risk with these skin colour categories. The Global UV Index forms an important part of the 'Sun Safety Code' developed by health organisations within the UK. (author)

The Global Solar UV Index used in the United Kingdom

Energy Technology Data Exchange (ETDEWEB)

New, C.; Driscoll, C.M.H.; Kitchen, K.; Miners, B

2000-07-01

Weather forecast bulletins on television, radio and in the newspapers in the UK now include advice about the strength of the ultraviolet (UV) radiation from the sun in terms of the Global Solar UV Index. A numerical scale of 1 to 20 is used to quote the Index for anywhere in the world and the Index addresses all ethnic groups. The Index replaces the sunburn warning system. The daily UV Index is calculated by the Met. Office from documented UV radiation levels and current atmospheric data and takes into account cloud cover forecast. Armed with the knowledge of the UV Index the public will be able to assess their personal risk of sun damage at home or abroad depending on their natural skin colour. Four categories of skin colour are identified with the Index; white skin that sunburns easily, white skin that tans readily, brown skin and black skin. A colour-coded rating from low to very high is used to identify personal risk with these skin colour categories. The Global UV Index forms an important part of the 'Sun Safety Code' developed by health organisations within the UK. (author)

Effect of heat, UV radiation, and moisture on the decohesion kinetics of inverted organic solar cells

KAUST Repository

Rolston, Nicholas

2017-06-15

Organic solar cells subjected to environmental stressors such as heat, moisture, and UV radiation can undergo significant mechanical degradation, leading to delamination of layers and device failure. This paper reports the effect these stressors have on the mechanical integrity of active layers and interfaces as measured by subcritical debonding tests, and the in situ evolution of defects and fracture processes is characterized. At elevated temperatures below 50 °C in inert conditions, significant device weakening was observed, an effect we attributed to a temperature-induced P3HT:PCBM delamination mechanism from the underlying ZnO. At 50 °C in ambient conditions with UV exposure—selected to better simulate real-world environments—devices were more resistant to fracture because of an interfacial strengthening effect from increased hydrogen bonding where UV-induced Zn(OH)2 formation reinforced the interface with P3HT:PCBM. This photoinduced hydroxylation mechanism was determined from a decrease in the Zn/O ratio with increased UVA or UVB exposure, and hydroxylation was shown to directly correlate with the resistance to fracture in devices.

Exclusion of solar UV radiation improves photosynthetic performance and yield of wheat varieties.

Science.gov (United States)

Kataria, Sunita; Guruprasad, K N

2015-12-01

Field studies were conducted to determine the potential for alterations in photosynthetic performance and grain yield of four wheat (Triticum aestivum) varieties of India- Vidisha, Purna, Swarna and Naveen Chandausi by ambient ultraviolet radiation (UV). The plants were grown in specially designed UV exclusion chambers, wrapped with filters that excluded UV-B (solar UV exclusion increased the leaf mass per area ratio, leaf weight ratio and chlorophylls per unit area of flag leaves in all the four varieties of wheat. Polyphasic chlorophyll a fluorescence transients from the flag leaves of UV excluded wheat plants gave a higher fluorescence yield. Exclusion of solar UV significantly enhanced photosynthetic performance as a consequence of increased efficiency of PS II, performance index (PIABS) and rate of photosynthesis in the flag leaves of wheat varieties along with a remarkable increase in carbonic anhydrase, Rubisco and nitrate reductase activities. This additional fixation of carbon and nitrogen by exclusion of UV was channelized towards the improvement in grain yield of wheat varieties as there was a decrease in the UV-B absorbing substances and an increase in soluble protein content in flag leaves of all the four varieties of wheat. The magnitude of response for UV exclusion for all the measured parameters was higher in two varieties of wheat Vidisha and Purna as compared to Swarna and Naveen Chandausi. Cumulative stress response index (CSRI) for each variety was developed from the cumulative sum of physiological and yield parameters such as leaf mass area ratio of flag leaf, total chlorophyll content, performance index at absorption basis, rate of photosynthesis and grain yield. All the varieties had a negative CSRI, demonstrating a negative impact of ambient UV radiation. Naveen Chandausi and Swarna are less sensitive to ambient UV radiation; Vidisha is more sensitive to both UV-A and UV-B and Purna is more sensitive to ambient UV-B radiation. Copyright �

Polycyclic aromatic hydrocarbons (PAHs) skin permeation rates change with simultaneous exposures to solar ultraviolet radiation (UV-S).

Science.gov (United States)

Hopf, Nancy B; Spring, Philipp; Hirt-Burri, Nathalie; Jimenez, Silvia; Sutter, Benjamin; Vernez, David; Berthet, Aurelie

2018-05-01

Road construction workers are simultaneously exposed to two carcinogens; solar ultraviolet (UV-S) radiation and polycyclic aromatic hydrocarbons (PAHs) in bitumen emissions. The combined exposure may lead to photogenotoxicity and enhanced PAH skin permeation rates. Skin permeation rates (J) for selected PAHs in a mixture (PAH-mix) or in bitumen fume condensate (BFC) with and without UV-S co-exposures were measured with in vitro flow-through diffusion cells mounted with human viable skin and results compared. Possible biomarkers were explored. Js were greater with UV-S for naphthalene, anthracene, and pyrene in BFC (0.08-0.1 ng/cm 2 /h) compared to without (0.02-0.26 ng/cm 2 /h). This was true for anthracene, pyrene, and chrysene in the PAH-mix. Naphthalene and benzo(a)pyrene (BaP) in the PAH-mix had greater Js without (0.97-13.01 ng/cm 2 /h) compared to with UV-S (0.40-6.35 ng/cm 2 /h). Time until permeation (T lags ) in the PAH-mix were generally shorter compared to the BFC, and they ranged from 1 to 13 h. The vehicle matrix could potentially be the reason for this discrepancy as BFC contains additional not identified substances. Qualitative interpretation of p53 suggested a dose-response with UV-S, and somewhat with the co-exposures. MMP1, p65 and cKIT were not exploitable. Although not statistically different, PAHs permeate human viable skin faster with simultaneous exposures to UV. Copyright © 2018 Elsevier B.V. All rights reserved.

Increased resistance of environmental anaerobic spores to inactivation by UV

NARCIS (Netherlands)

Hijnen, W.A.M.; Veer, A.J. van der; Beerendonk, E.F.; Medema, Gerriet Jan

2004-01-01

Water Company Europoort started a pilot plant (MP)UV study to determine the UV-fluence to meet the Dutch drinking water standards. The results of large volume sampling of this pilot plant demonstrated that environmental spores of sulphite-reducing clostridia (SSRC) were highly resistant against UV.

77 FR 22331 - Submission for OMB Review; Comment Request; Solar Cell: A Mobile UV Manager for Smart Phones...

Science.gov (United States)

2012-04-13

... DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Submission for OMB Review; Comment Request; Solar Cell: A Mobile UV Manager for Smart Phones Phase II (NCI) Summary: Under the... control number. Proposed Collection: Title: Solar Cell: A Mobile UV Manager for Smart Phones Phase II (NCI...

Solar UV exposure among outdoor workers in Denmark measured with personal UV-B dosimeters: technical and practical feasibility.

Science.gov (United States)

Grandahl, Kasper; Mortensen, Ole Steen; Sherman, David Zim; Køster, Brian; Lund, Paul-Anker; Ibler, Kristina Sophie; Eriksen, Paul

2017-10-10

Exposure to solar ultraviolet radiation is a well-known cause of skin cancer. This is problematic for outdoor workers. In Denmark alone, occupational skin cancer poses a significant health and safety risk for around 400,000 outdoor workers. Objective measures of solar ultraviolet radiation exposure are needed to help resolve this problem. This can be done using personal ultraviolet radiation dosimeters. We consider technical and practical feasibility of measuring individual solar ultraviolet exposure at work and leisure in professions with different á priori temporal high-level outdoor worktime, using aluminium gallium nitride (AlGaN) photodiode detector based personal UV-B dosimeters. Essential technical specifications including the spectral and angular responsivity of the dosimeters are described and pre-campaign dosimeter calibration applicability is verified. The scale and conduct of dosimeter deployment and campaign in-field measurements including failures and shortcomings affecting overall data collection are presented. Nationwide measurements for more than three hundred and fifty workers from several different professions were collected in the summer of 2016. On average, each worker's exposure was measured for a 2-week period, which included both work and leisure. Data samples of exposure at work during a Midsummer day show differences across professions. A construction worker received high-level occupational UV exposure most of the working day, except during lunch hour, accumulating to 5.1 SED. A postal service worker was exposed intermittently around noon and in the afternoon, preceded by no exposure forenoon when packing mail, accumulating to 1.6 SED. A crane fitter was exposed only during lunch hour, accumulating to 0.7 SED. These findings are in line with our specialist knowledge as occupational physicians. Large-scale use of personal UV-B dosimeters for measurement of solar ultraviolet radiation exposure at work and leisure in Denmark is indeed

Molecular cloning of the human gene SUVCC3 associated with the formation of DNA-protein crosslinks following exposure to solar UV radiation

International Nuclear Information System (INIS)

Rosenstein, B.S.; Vaslet, C.A.

1995-01-01

DRP 153 cells, which are hypersensitive to solar UV and deficient in the formation of DNA-protein crosslinks (DPC) following irradiation, were transfected with human DNA and a secondary transformant obtained in which a normal DPC response and solar UV sensitivity reestablished. DNA from this secondary transformant was used to construct a genomic DNA library from which a recombinant phage was isolated containing the human gene capable of restoring a normal DPC response and solar UV sensitivity to DRP 153. This gene has been designated SUVCC3 to denote solar UV cross-complementing gene number 3. 27 refs., 5 figs., 2 tabs

Effect of solar UV/EUV heating on the intensity and spatial distribution of Jupiter's synchrotron radiation

Science.gov (United States)

Kita, H.; Misawa, H.; Tsuchiya, F.; Tao, C.; Morioka, A.

2013-10-01

We analyzed the Very Large Array archived data observed in 2000 to determine whether solar ultraviolet (UV)/extreme ultraviolet (EUV) heating of the Jovian thermosphere causes variations in the total flux density and dawn-dusk asymmetry (the characteristic differences between the peak emissions at dawn and dusk) of Jupiter's synchrotron radiation (JSR). The total flux density varied by 10% over 6 days of observations and accorded with theoretical expectations. The average dawn-dusk peak emission ratio indicated that the dawn side emissions were brighter than those on the dusk side and this was expected to have been caused by diurnal wind induced by the solar UV/EUV. The daily variations in the dawn-dusk ratio did not correspond to the solar UV/EUV, and this finding did not support the theoretical expectation that the dawn-dusk ratio and diurnal wind velocity varies in correspondence with the solar UV/EUV. We tried to determine whether the average dawn-dusk ratio could be explained by a reasonable diurnal wind velocity. We constructed an equatorial brightness distribution model of JSR using the revised Divine-Garrett particle distribution model and used it to derive a relation between the dawn-dusk ratio and diurnal wind velocity. The estimated diurnal wind velocity reasonably corresponded to a numerical simulation of the Jovian thermosphere. We also found that realistic changes in the diurnal wind velocity could not cause the daily variations in the dawn-dusk ratio. Hence, we propose that the solar UV/EUV related variations were below the detection limit and some other processes dominated the daily variations in the dawn-dusk ratio.

The solar UV environment and bacterial spore UV resistance: considerations for Earth-to-Mars transport by natural processes and human spaceflight

Science.gov (United States)

Nicholson, Wayne L.; Schuerger, Andrew C.; Setlow, Peter

2005-01-01

The environment in space and on planets such as Mars can be lethal to microorganisms because of the high vacuum and high solar radiation flux, in particular UV radiation, in such environments. Spores of various Bacillus species are among the organisms most resistant to the lethal effects of high vacuum and UV radiation, and as a consequence are of major concern for planetary contamination via unmanned spacecraft or even natural processes. This review focuses on the spores of various Bacillus species: (i) their mechanisms of UV resistance; (ii) their survival in unmanned spacecraft, space flight and simulated space flight and Martian conditions; (iii) the UV flux in space and on Mars; (iv) factors affecting spore survival in such high UV flux environments.

The solar UV environment and bacterial spore UV resistance: considerations for Earth-to-Mars transport by natural processes and human spaceflight

International Nuclear Information System (INIS)

Nicholson, Wayne L.; Schuerger, Andrew C.; Setlow, Peter

2005-01-01

The environment in space and on planets such as Mars can be lethal to microorganisms because of the high vacuum and high solar radiation flux, in particular UV radiation, in such environments. Spores of various Bacillus species are among the organisms most resistant to the lethal effects of high vacuum and UV radiation, and as a consequence are of major concern for planetary contamination via unmanned spacecraft or even natural processes. This review focuses on the spores of various Bacillus species: (i) their mechanisms of UV resistance; (ii) their survival in unmanned spacecraft, space flight and simulated space flight and Martian conditions; (iii) the UV flux in space and on Mars; (iv) factors affecting spore survival in such high UV flux environments

The solar UV environment and bacterial spore UV resistance: considerations for Earth-to-Mars transport by natural processes and human spaceflight

Energy Technology Data Exchange (ETDEWEB)

Nicholson, Wayne L. [Department of Microbiology and Cell Science, University of Florida, Mail Code UF-1, Building M6-1025/SLSL, Kennedy Space Center, FL 32899 (United States)]. E-mail: WLN@ufl.edu; Schuerger, Andrew C. [Department of Plant Pathology, University of Florida, Mail Code UF-1, Space Life Sciences Laboratory, Kennedy Space Center, FL 32899 (United States)]. E-mail: acschuerger@ifas.ufl.edu; Setlow, Peter [Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030 (United States)]. E-mail: setlow@nso2.uchc.edu

2005-04-01

The environment in space and on planets such as Mars can be lethal to microorganisms because of the high vacuum and high solar radiation flux, in particular UV radiation, in such environments. Spores of various Bacillus species are among the organisms most resistant to the lethal effects of high vacuum and UV radiation, and as a consequence are of major concern for planetary contamination via unmanned spacecraft or even natural processes. This review focuses on the spores of various Bacillus species: (i) their mechanisms of UV resistance; (ii) their survival in unmanned spacecraft, space flight and simulated space flight and Martian conditions; (iii) the UV flux in space and on Mars; (iv) factors affecting spore survival in such high UV flux environments.

Effects of environmental and artificial UV-B radiation on freshwater prawn Macrobrachium olfersi embryos

Energy Technology Data Exchange (ETDEWEB)

Nazari, Evelise Maria [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil); Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Ammar, Dib [Universidade do Oeste de Santa Catarina, Departamento de Biologia, Campus Universitario, 89600-000 Joacaba, SC (Brazil); Bem, Andreza Fabro de; Latini, Alexandra [Universidade Federal de Santa Catarina, Departamento de Bioquimica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Mueller, Yara Maria Rauh [Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Allodi, Silvana, E-mail: sallodi@histo.ufrj.br [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil)

2010-06-01

The recent decrease of the stratospheric ozone has resulted in an increase of ultraviolet-B (UV-B) radiation reaching the Earth's surface. In freshwater ecosystems with transparent water, UV-B rays easily penetrate and potentially cause harmful effects to organisms. In this study, embryos of the prawn Macrobrachium olfersi were used to evaluate the impact of UV-B rays in freshwater environments. We observed three groups of embryos: the first was to assess whether UV-B radiation produced morphological defects and/or biochemical impairments in the laboratory. The second was to check whether embryos with the same impairments as those observed in the laboratory were found in their environment, under natural solar radiation. The third group was the non-irradiated control. The embryos irradiated with 310 mW cm{sup -2} UV-B for 30 min showed morphological alterations similar to those observed in embryos from the environmental control group. The most important effects of the UV-B radiation observed in M. olfersi embryos were morphological (1.2% of the total number of embryos from the environment and 2.8% of the total number of irradiated embryos), pigmentation changes in the eyes (78.0% of the total number of embryos from the environment and 98.9% of the total number of irradiated embryos), and disruption of the chromatophores (46.9% of the total number of embryos from the environment and 95.5% of the total number of irradiated embryos). We also observed an increase in egg volume, which was accompanied by a significant increase in water content in UV-B irradiated groups when compared with aquaria control embryos. In addition, a significant decrease in the mitotic index in eggs exposed to UV-B radiation was detected (0.17 for the embryos from the aquaria control, 0.10 for the embryos of the environmental control, and 0.04 for the irradiated groups). The low levels of NPSH and high levels of TBARS indicated that UV-B rays directly compromised the antioxidant function of

Effects of environmental and artificial UV-B radiation on freshwater prawn Macrobrachium olfersi embryos

International Nuclear Information System (INIS)

Nazari, Evelise Maria; Ammar, Dib; Bem, Andreza Fabro de; Latini, Alexandra; Mueller, Yara Maria Rauh; Allodi, Silvana

2010-01-01

The recent decrease of the stratospheric ozone has resulted in an increase of ultraviolet-B (UV-B) radiation reaching the Earth's surface. In freshwater ecosystems with transparent water, UV-B rays easily penetrate and potentially cause harmful effects to organisms. In this study, embryos of the prawn Macrobrachium olfersi were used to evaluate the impact of UV-B rays in freshwater environments. We observed three groups of embryos: the first was to assess whether UV-B radiation produced morphological defects and/or biochemical impairments in the laboratory. The second was to check whether embryos with the same impairments as those observed in the laboratory were found in their environment, under natural solar radiation. The third group was the non-irradiated control. The embryos irradiated with 310 mW cm -2 UV-B for 30 min showed morphological alterations similar to those observed in embryos from the environmental control group. The most important effects of the UV-B radiation observed in M. olfersi embryos were morphological (1.2% of the total number of embryos from the environment and 2.8% of the total number of irradiated embryos), pigmentation changes in the eyes (78.0% of the total number of embryos from the environment and 98.9% of the total number of irradiated embryos), and disruption of the chromatophores (46.9% of the total number of embryos from the environment and 95.5% of the total number of irradiated embryos). We also observed an increase in egg volume, which was accompanied by a significant increase in water content in UV-B irradiated groups when compared with aquaria control embryos. In addition, a significant decrease in the mitotic index in eggs exposed to UV-B radiation was detected (0.17 for the embryos from the aquaria control, 0.10 for the embryos of the environmental control, and 0.04 for the irradiated groups). The low levels of NPSH and high levels of TBARS indicated that UV-B rays directly compromised the antioxidant function of the

Very high resolution UV and X-ray spectroscopy and imagery of solar active regions

Science.gov (United States)

Bruner, M.; Brown, W. A.; Haisch, B. M.

1987-01-01

A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft X-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the X-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical X-ray observations using this new technique.

Focal plane instrument for the Solar UV-Vis-IR Telescope aboard SOLAR-C

Science.gov (United States)

Katsukawa, Yukio; Suematsu, Yoshinori; Shimizu, Toshifumi; Ichimoto, Kiyoshi; Takeyama, Norihide

2011-10-01

It is presented the conceptual design of a focal plane instrument for the Solar UV-Vis-IR Telescope (SUVIT) aboard the next Japanese solar mission SOLAR-C. A primary purpose of the telescope is to achieve precise as well as high resolution spectroscopic and polarimetric measurements of the solar chromosphere with a big aperture of 1.5 m, which is expected to make a significant progress in understanding basic MHD processes in the solar atmosphere. The focal plane instrument consists of two packages: A filtergraph package is to get not only monochromatic images but also Dopplergrams and magnetograms using a tunable narrow-band filter and interference filters. A spectrograph package is to perform accurate spectro-polarimetric observations for measuring chromospheric magnetic fields, and is employing a Littrow-type spectrograph. The most challenging aspect in the instrument design is wide wavelength coverage from 280 nm to 1.1 μm to observe multiple chromospheric lines, which is to be realized with a lens unit including fluoride glasses. A high-speed camera for correlation tracking of granular motion is also implemented in one of the packages for an image stabilization system, which is essential to achieve high spatial resolution and high polarimetric accuracy.

Measuring solar UV radiation with EBT radiochromic film

International Nuclear Information System (INIS)

Butson, Ethan T; Cheung Tsang; Yu, Peter K N; Butson, Martin J

2010-01-01

Ultraviolet radiation dosimetry has been performed with the use of a radiochromic film dosimeter called Gafchromic EBT for solar radiation exposure. The film changes from a clear colour to blue colour when exposed to ultraviolet radiation and results have shown that the colour change is reproducible within ±10% at 5 kJ m -2 UV exposure under various conditions of solar radiation. Parameters tested included changes in season (summer versus winter exposure), time of day, as well as sky conditions such as cloudy skies versus clear skies. As the radiochromic films' permanent colour change occurs in the visible wavelengths the film can be analysed with a desktop scanner with the most sensitive channel for analysis being the red component of the signal. Results showed that an exposure of 5 kJ m -2 (approximately 1 h exposure in full sun during summer) produced an approximate 0.28 change in the net OD when analysed in reflection mode on the desktop scanner which is significant darkening. The main advantages of this film type, and thus the new EBT2 film which has replaced EBT for measurement of UV exposure, is the visible colour change and thus easy analysis using a desktop scanner, its uniformity in response and its robust physical strength for use in outside exposure situations. (note)

Differential responses of tetrasporophytes and gametophytes of Mazzaella laminarioides (Gigartinales, Rhodophyta) under solar UV radiation.

Science.gov (United States)

Navarro, Nelso P; Figueroa, Félix L; Korbee, Nathalie; Mansilla, Andrés; Plastino, Estela M

2016-06-01

The effects of solar UV radiation on mycosporine-like amino acids (MAAs), growth, photosynthetic pigments (Chl a, phycobiliproteins), soluble proteins (SP), and C and N content of Mazzaella laminarioides tetrasporophytes and gametophytes were investigated. Apical segments of tetrasporophytes and gametophytes were exposed to solar radiation under three treatments (PAR [P], PAR+UVA [PA], and PAR+UVA+UVB [PAB]) during 18 d in spring 2009, Punta Arenas, Chile. Samples were taken after 2, 6, 12, and 18 d of solar radiation exposure. Most of the parameters assessed on M. laminarioides were significantly influenced by the radiation treatment, and both gametophytes and tetrasporophytes seemed to respond differently when exposed to high UV radiation. The two main effects promoted by UV radiation were: (i) higher synthesis of MAAs in gametophytes than tetrasporophytes at 2 d, and (ii) a decrease in phycoerythrin, phycocyanin, and SPs, but an increase in MAA content in tetrasporophytes at 6 and 12 d of culture. Despite some changes that were observed in biochemical parameters in both tetrasporophytes and gametophytes of M. laminarioides when exposed to UVB radiation, these changes did not promote deleterious effects that might interfere with the growth in the long term (18 d). The tolerance and resistance of M. laminarioides to higher UV irradiance were expected, as this intertidal species is exposed to variation in solar radiation, especially during low tide. © 2016 Phycological Society of America.

How do environmental and behavioral factors impact ultraviolet radiation effects on health: the RISC-UV Project

Science.gov (United States)

Correa, M. P.; Godin-Beekmann, S.; Haeffelin, M.; Saiag, P.; Mahe, E.; Brogniez, C.; Dupont, J. C.; Pazmiño, A.; Auriol, F.; Bonnel, B.

2009-04-01

Introduction: RISC-UV is a research project on "Impact of climate change on ultraviolet radiation and risks for health", a research project in which physicists, meteorologists and physicians work together to assess the relative role played by environmental and behavioral factors in the UV-related diseases as skin cancer and vitamin D deficiency. Environmental factors are related to the role played by the alteration in intensity of UV radiation at the Earth's surface resulting from variation in several factors affected by climate change and human activities: stratospheric ozone, cloud cover, aerosols and the reflectivity of the surface. On the other hand, behavioral factors are related to the sun over/underexposure and the correct use of sun-protection (hats, caps, sunglasses, sunscreen lotion, etc.). RISC-UV is organized around three main areas: 1) Organization of a workshop, scheduled for January 2009, which aims to describe the state of the art in the subject within each community and define the requirements of pathologists for epidemiological studies; 2) A pilot study intended to evaluate the consistency between UV measurements delivered simultaneously by satellite-based instruments, ground instruments, radiometers and individual dosimeters. This study is based on measurements campaigns and an analysis of the long-term consistency of data series relating to UV radiation and associated parameters; and 3) Analysis of the weights of medical, behavioral and environmental parameters involved in skin carcinogenesis. A detailed description of these areas can be found in http://www.gisclimat.fr/Doc/GB/D_projects/RISC-UV_GB.html. This presentation focuses on the first results of the UV experimental measurements performed between September 8th and October 8th 2008 in Palaiseau, France (48.7˚ N; 2.2˚ E; 170m - Haeffelin et al., 2005). A second campaign is foreseen for the spring of 2009. The purpose of these campaigns is to obtain, analyze and quantitatively link the

Effectiveness of Sunscreen at Preventing Solar UV-Induced Alterations of Human Stratum Corneum

Science.gov (United States)

Martinez, O.; Dauskardt, R.; Biniek, K.; Novoa, F.

2012-12-01

The outermost layer of the epidermis, the stratum corneum, protects the body from harmful environmental conditions by serving as a selective barrier. Solar ultraviolet (UV) radiation is one of the most common conditions the body encounters and is responsible for many negative skin responses, including compromised barrier function. UV exposure has dramatic effects on stratum corneum cell cohesion and mechanical integrity that are related to its effects on the stratum corneum's intercellular lipids. Hypothesis Sunscreen contains chemicals that absorb UV radiation to prevent the radiation from penetrating the skin. Thus, it is expected that the application of sunscreen on human stratum corneum will reduce UV-induced alterations of human stratum corneum. Procedures/Equipment Human tissue was processed in order to isolate the stratum corneum, the top layer of the epidermis. Double cantilever beam (DCB) testing was used to study the effect of UV radiation on human stratum corneum. Two different types of DCB samples were created: control DCB samples with the application of carrier and UV light to the stratum corneum and DCB samples with the application of sunscreen and UV light to the stratum corneum. For the control sample, one side of the stratum corneum was glued to a polycarbonate beam and carrier was applied. Then, the sample was placed 10 cm away from the UV lamp inside of the environmental chamber and were exposed to UV dosages of about 800 J/cm2. Once this step was complete, a second polycarbonate beam was glued to the other side of the stratum corneum. The steps were similar for the DCB sample that had sunscreen applied and that was exposed to UV light. After gluing one side of the stratum corneum to a polycarbonate beam, Octinoxate sunscreen was applied. The next steps were similar to those of the control sample. All DCB samples were then let out to dry for two hours in a dry box in order for the moisture from the lab to be extracted. Each DCB sample was tested

Photocatalytic degradation of aniline using an autonomous rotating drum reactor with both solar and UV-C artificial radiation.

Science.gov (United States)

Durán, A; Monteagudo, J M; San Martín, I; Merino, S

2018-03-15

The aim of this work was to evaluate the performance of a novel self-autonomous reactor technology (capable of working with solar irradiation and artificial UV light) for water treatment using aniline as model compound. This new reactor design overcomes the problems of the external mass transfer effect and the accessibility to photons occurring in traditional reaction systems. The UV-light source is located inside the rotating quartz drums (where TiO 2 is immobilized), allowing light to easily reach the water and the TiO 2 surface. Several processes (UV, H 2 O 2 , Solar, TiO 2 , Solar/TiO 2 , Solar/TiO 2 /H 2 O 2 and UV/Solar/H 2 O 2 /TiO 2 ) were tested. The synergy between Solar/H 2 O 2 and Solar/TiO 2 processes was quantified to be 40.3% using the pseudo-first-order degradation rate. The apparent photonic efficiency, ζ, was also determined for evaluating light utilization. For the Solar/TiO 2 /H 2 O 2 process, the efficiency was found to be practically constant (0.638-0.681%) when the film thickness is in the range of 1.67-3.87 μm. However, the efficiency increases up to 2.67% when artificial UV light was used in combination, confirming the efficient design of this installation. Thus, if needed, lamps can be switched on during cloudy days to improve the degradation rate of aniline and its mineralization. Under the optimal conditions selected for the Solar/TiO 2 /H 2 O 2 process ([H 2 O 2 ] = 250 mg/L; pH = 4, [TiO 2 ] = 0.65-1.25 mg/cm 2 ), 89.6% of aniline is degraded in 120 min. If the lamps are switched on, aniline is completely degraded in 10 min, reaching 85% of mineralization in 120 min. TiO 2 was re-used during 5 reaction cycles without apparent loss in activity (Solar/TiO 2 /H 2 O 2 process was found to have lower operation costs than other systems described in literature (0.67 €/m 3 ). Copyright © 2018 Elsevier Ltd. All rights reserved.

METIS: the visible and UV coronagraph for solar orbiter

Science.gov (United States)

Romoli, M.; Landini, F.; Antonucci, E.; Andretta, V.; Berlicki, A.; Fineschi, S.; Moses, J. D.; Naletto, G.; Nicolosi, P.; Nicolini, G.; Spadaro, D.; Teriaca, L.; Baccani, C.; Focardi, M.; Pancrazzi, M.; Pucci, S.; Abbo, L.; Bemporad, A.; Capobianco, G.; Massone, G.; Telloni, D.; Magli, E.; Da Deppo, V.; Frassetto, F.; Pelizzo, M. G.; Poletto, L.; Uslenghi, M.; Vives, S.; Malvezzi, M.

2017-11-01

METIS coronagraph is designed to observe the solar corona with an annular field of view from 1.5 to 2.9 degrees in the visible broadband (580-640 nm) and in the UV HI Lyman-alpha, during the Sun close approaching and high latitude tilting orbit of Solar Orbiter. The big challenge for a coronagraph is the stray light rejection. In this paper after a description of the present METIS optical design, the stray light rejection design is presented in detail together with METIS off-pointing strategies throughout the mission. Data shown in this paper derive from the optimization of the optical design performed with Zemax ray tracing and from laboratory breadboards of the occultation system and of the polarimeter.

Solar UV-B radiation and ethylene play a key role in modulating effective defenses against Anticarsia gemmatalis larvae in field-grown soybean.

Science.gov (United States)

Dillon, Francisco M; Tejedor, M Daniela; Ilina, Natalia; Chludil, Hugo D; Mithöfer, Axel; Pagano, Eduardo A; Zavala, Jorge A

2018-02-01

Solar UV-B radiation has been reported to enhance plant defenses against herbivore insects in many species. However, the mechanism and traits involved in the UV-B mediated increment of plant resistance are unknown in crops species, such as soybean. Here, we studied defense-related responses in undamaged and Anticarsia gemmatalis larvae-damaged leaves of two soybean cultivars grown under attenuated or full solar UV-B radiation. We determined changes in jasmonates, ethylene (ET), salicylic acid, trypsin protease inhibitor activity, flavonoids, and mRNA expression of genes related with defenses. ET emission induced by Anticarsia gemmatalis damage was synergistically increased in plants grown under solar UV-B radiation and was positively correlated with malonyl genistin concentration, trypsin proteinase inhibitor activity and expression of IFS2, and the pathogenesis protein PR2, while was negatively correlated with leaf consumption. The precursor of ET, aminocyclopropane-carboxylic acid, applied exogenously to soybean was sufficient to strongly induce leaf isoflavonoids. Our results showed that in field-grown soybean isoflavonoids were regulated by both herbivory and solar UV-B inducible ET, whereas flavonols were regulated by solar UV-B radiation only and not by herbivory or ET. Our study suggests that, although ET can modulate UV-B-mediated priming of inducible plant defenses, some plant defenses, such as isoflavonoids, are regulated by ET alone. © 2017 John Wiley & Sons Ltd.

Medición y predicción de la radiación solar global UV-B bajo cielos claros y sin nubes

Directory of Open Access Journals (Sweden)

Jaime Wright Gilmore

2016-03-01

Full Text Available Se presentan mediciones experimentales de la radiación solar ultravioleta en el rango B del espectro solar (UV-B y la radiación ultravioleta en el rango total RUV (UV-A+UV-B en días claros y sin nubes en Heredia, Costa Rica. Se utilizó una radiómetro UV-B, que mide la radiación solar en el rango espectral 280-315 nm, y un radiómetro RUV, que mide la radiación solar en el rango espectral 280-385 nm. La dependencia entre entre UV-B y RUV también fue investigada, y se encontró un excelente grado de asociación entre ambas. Además se detalló que UV-B representa solamente un 5,4% de RUV, a pesar de que UV-B es mil veces más potente que UV-A. Los valores de UV-B medidos in situ fueron comparados con los valores predichos por un modelo atmosférico espectral, el cual utiliza como datos de entrada: la hora del día, la latitud, la altitud, el albedo superficial, la distancia Tierra-Sol, la turbiedad atmosférica y el ozono atmosférico. La comparación entre los valores medidos y predichos dio resultados satisfactorios.

Impact of UV Radiation on Genome Stability and Human Health.

Science.gov (United States)

Roy, Sujit

2017-01-01

Gradual depletion of the atmospheric ozone layer during the past few years has increased the incidence of solar UV radiation specifically the UV-C on earth's surface is one of the major environmental concerns because of the harmful effects of this radiation in all forms of life. The solar UV radiation including the harmful wavelength range of UV-B (280-320 nm) represents a significant climatic stress for both animals and plants, causing damage to the fundamental biomolecules such as DNA, proteins and lipids, thus activating genotoxic stress and induces genome instability. When DNA absorbs UV-B light, energy from the photon causes covalent linkages to form between adjacent pyrimidine bases, creating photoproducts, primarily cyclobutane pyrimidine dimers (CPDs) and pyrimidine-6,4-pyrimidinone photoproduct (6,4PPs). Pyrimidine dimers create distortions in the DNA strands and therefore can inhibit DNA replication as well transcription. Lack of efficient repair of UV-induced DNA damage may induce the formation of DNA double stand breaks (DSBs), one of the serious forms of damage in DNA double helix, as well as oxidative damage. Unrepaired DSBs in the actively dividing somatic cells severely affect cell growth and development, finally results in loss of cell viability and development of various diseases, such as cancer in man.This chapter mainly highlights the incidence of solar UV-radiation on earth's surface along with the formation of major types of UV-induced DNA damage and the associated repair mechanisms as well as methods of detecting DNA damage and finally our present understanding on the impact on solar UV radiation on human health.

Effects of Stratospheric Ozone Depletion, Solar UV Radiation, and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

Science.gov (United States)

Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment...

Efficiency enhancement of silicon nanowire solar cells by using UV/Ozone treatments and micro-grid electrodes

Science.gov (United States)

Chen, Junyi; Subramani, Thiyagu; Sun, Yonglie; Jevasuwan, Wipakorn; Fukata, Naoki

2018-05-01

Silicon nanowire solar cells were fabricated by metal catalyzed electroless etching (MCEE) followed by thermal chemical vapor deposition (CVD). In this study, we investigated two effects, a UV/ozone treatment and the use of a micro-grid electrodes, to enhance light absorption and reduce the optic losses in the solar cell device. The UV/ozone treatment successfully improved the conversion efficiency. The micro-grid electrodes were then applied in solar cell devices subjected to a back surface field (BSF) treatment and rapid thermal annealing (RTA). These effects improved the conversion efficiency from 9.4% to 10.9%. Moreover, to reduce surface recombination and improve the continuity of front electrodes, we optimized the etching time of the MCEE process, giving a high efficiency of 12.3%.

Compact solar UV burst triggered in a magnetic field with a fan-spine topology

Science.gov (United States)

Chitta, L. P.; Peter, H.; Young, P. R.; Huang, Y.-M.

2017-09-01

Context. Solar ultraviolet (UV) bursts are small-scale features that exhibit intermittent brightenings that are thought to be due to magnetic reconnection. They are observed abundantly in the chromosphere and transition region, in particular in active regions. Aims: We investigate in detail a UV burst related to a magnetic feature that is advected by the moat flow from a sunspot towards a pore. The moving feature is parasitic in that its magnetic polarity is opposite to that of the spot and the pore. This comparably simple photospheric magnetic field distribution allows for an unambiguous interpretation of the magnetic geometry leading to the onset of the observed UV burst. Methods: We used UV spectroscopic and slit-jaw observations from the Interface Region Imaging Spectrograph (IRIS) to identify and study chromospheric and transition region spectral signatures of said UV burst. To investigate the magnetic topology surrounding the UV burst, we used a two-hour-long time sequence of simultaneous line-of-sight magnetograms from the Helioseismic and Magnetic Imager (HMI) and performed data-driven 3D magnetic field extrapolations by means of a magnetofrictional relaxation technique. We can connect UV burst signatures to the overlying extreme UV (EUV) coronal loops observed by the Atmospheric Imaging Assembly (AIA). Results: The UV burst shows a variety of extremely broad line profiles indicating plasma flows in excess of ±200 km s-1 at times. The whole structure is divided into two spatially distinct zones of predominantly up- and downflows. The magnetic field extrapolations show a persistent fan-spine magnetic topology at the UV burst. The associated 3D magnetic null point exists at a height of about 500 km above the photosphere and evolves co-spatially with the observed UV burst. The EUV emission at the footpoints of coronal loops is correlated with the evolution of the underlying UV burst. Conclusions: The magnetic field around the null point is sheared by

First performance results of two novel spectroradiometers developed for fast scanning of solar spectra UV irradiance

Science.gov (United States)

Feister, Uwe; Kaifel, Anton K.; Grewe, Rolf-Dieter; Kaptur, Jasmine; Reutter, Oliver; Wohlfart, Michael; Gericke, Klaus

2003-11-01

Two recently developed different types of fast spectroradiometers measuring solar UV irradiance have been compared in a field campaign: i) the UV spectroradiometer on filter model basis (UV-SPRAFIMO) and ii) the modified version of the spectroradiometer SPECTRO 320D by Instrument Systems. The all-weather UV-SPRAFIMO instrument combines a UV filter radiometer with 5 narrow-band (FBHM ~ 2.0 to 2.5 nm) filters centered within +/- 0.01 nm at 303.5, 309.0, 314.5, 327.0 and 387.0 nm, and an advanced neural network-based model. It allows up to 5 measurements per second to be taken that are averaged within time intervals between 5 and 30 s. The neural networks model that is embedded in the PC-based processing software converts the 5 measured irradiances into a full spectrum from 280 to 450 nm at small wavelength steps (>= 0.05 nm). These spectra can be convoluted with user-defined slit function and integrated to broad-band and action-spectra-weighted irradiance values. Users can access the data stored in the internal data logger by a serial RS232 interface or by a modem and display them on a PC-based Graphical User Interface. The spectroradiometer SPECTRO320D consists of a grating double monochromator with a cooled (-20°C) PMT receiver. The modified instrument version run by DWD uses a Schreder type cosine diffuser that directs the solar global irradiance via quartz fiber optics onto the spectroradiometer's entrance slit. The spectroradiometer used at the campaign was installed in a thermostatted (22 +/- 0.02)°C aluminum box. The modified instrument version performs a spectral scan over the whole UV region in two subsequent parts, with a lower speed in the UV-B than in the UV-A to account for the exponential changes of solar irradiance with increasing wavelengths in the UV-B and for the almost linear change in the UV-A region. In the configuration applied in the comparison, i.e. wavelength steps of 0.2 nm within the scan range from 290 nm to 450 nm, the resulting scan

Synthesis, characterization and photocatalytic activity of ZnO flower and pseudo-sphere: Nonylphenol ethoxylate degradation under UV and solar irradiation

Energy Technology Data Exchange (ETDEWEB)

Ashar, Ambreen [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan); Iqbal, Munawar, E-mail: bosalvee@yahoo.com [Department of Chemistry, Qurtuba University of Science and Information Technology, Peshawar 25100, KPK (Pakistan); Bhatti, Ijaz Ahmad; Ahmad, Muhammad Zubair; Qureshi, Khizar [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan); Nisar, Jan [National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120 (Pakistan); Bukhari, Iftikhar Hussain [Department of Chemistry, Government College University, Faisalabad (Pakistan)

2016-09-05

ZnO particles (flower and pseudo sphere) were synthesized via precipitation route and characterized using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), Fourier transform infra-red (FTIR) spectroscopy, Atomic force microscopy (AFM), Particle size analyzer and UV–visible techniques. The photocatalytic activities (PCA) of ZnO flower (uncalcined) and pseudo-sphere (calcined) were evaluated by degrading nonylphenol ethoxylate-9 (NP9EO) under UV and solar irradiation. The process variables i.e., catalyst dose, calcination temperature, H{sub 2}O{sub 2} concentration, pH and UV/solar light exposure were investigated and under optimum conditions of process variables, paper, textile and leather industries effluents were also treated. Calcination at high temperature affected the morphology of ZnO particles. Both ZnO flower and pseudo-sphere degraded NP9EO and pollutants in industrial wastewater efficiently under both UV and solar irradiation. Maximum NP9EO degradation was achieved at 2.5 g/L catalyst dose, high calcination temperature, 4% H{sub 2}O{sub 2} concentration, 6 pH, 110 UV exposure and 12 h solar light exposure. Results reveal that ZnO is efficient photo-catalyst and could be used under solar irradiation for photocatalytic application by tuning the band gap. - Highlights: • ZnO flower and pseudo-spheres were synthesized via precipitation route. • The photocatalytic activities by degrading surfactant. • ZnO particles showed considerable photocatalytic activity under UV and solar irradiation. • By tuning the band gap of ZnO absorption capacity can be enhanced.

Ozone changes under solar geoengineering: implications for UV exposure and air quality

Science.gov (United States)

Nowack, P. J.; Abraham, N. L.; Braesicke, P.; Pyle, J. A.

2015-11-01

Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term Solar Radiation Management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks such as ozone changes under this scenario. Including the composition changes, we find large reductions in surface UV-B irradiance, with implications for vitamin D production, and increases in surface ozone concentrations, both of which could be important for human health. We highlight that both tropospheric and stratospheric ozone changes should be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

UV reflectance is associated with environmental conditions in Palaearctic Pieris napi (Lepidoptera: Pieridae).

Science.gov (United States)

Stella, David; Pecháček, Pavel; Meyer-Rochow, Victor Benno; Kleisner, Karel

2018-06-01

The subject of our investigation was the visual features of wing color with special focus on the UV reflectance in the green-veined white butterfly (Pieris napi). Previous studies had concluded that UV reflectance on dorsal wing surfaces is found only in the female P. napi. Based on UV sensitive photography, we analyzed a correlation between 12 geographic and environmental factors and UV reflectance patterns on 3 patches on the forewings of 407 P. napi specimens from the Palaearctic region. Results had shown that females significantly differ from males: they exhibit a 25% higher UV reflectance. To investigate whether and how UV reflectance levels on the forewings and hindwings of both sexes are influenced by the environment, we performed a principal component analysis (PCA) with several environmental variables. For several variables (in particular, latitude and longitude, mean annual temperature and precipitation, and temperature annual range and altitude), the generalized linear model (GLM) model revealed a significant correlation in both sexes. This suggests a link between UV reflectance levels and the environment and distribution of P. napi. We found that stronger UV reflectance is associated with generally more hostile environments and concluded that large-scale environmental factors influence the UV reflectance on the forewings of both male and female green-veined white butterflies. © 2016 Institute of Zoology, Chinese Academy of Sciences.

Impact of solar UV radiation on toxicity of ZnO nanoparticles through photocatalytic reactive oxygen species (ROS) generation and photo-induced dissolution

Science.gov (United States)

The present study investigated the impact of solar UV radiation on ZnO nanoparticle toxicity through photocatalytic ROS generation and photo-induced dissolution. Toxicity of ZnO nanoparticles to Daphnia magna was examined under laboratory light versus simulated solar UV radiatio...

Photocatalytic ROS production and phototoxicity of titanium dioxide nanoparticles is dependent on solar UV radiation spectrum

Science.gov (United States)

Generation of reactive oxygen species (ROS) by titanium dioxide nanoparticles (nano-TiO2) and its consequent phototoxicity to Daphnia magna were measured under different solar UV radiation spectrum by applying a series of optical filters in a solar simulator. Removing UVB (280-32...

Very high resolution UV and x-ray spectroscopy and imagery of solar active regions. Final report

International Nuclear Information System (INIS)

Bruner, M.; Brown, W.A.; Haisch, B.M.

1987-01-01

A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft x-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the x-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical x-ray observations using this new technique

Seasonal responses of six Poaceae to differential levels of solar UV-B radiation

International Nuclear Information System (INIS)

Deckmyn, G.; Impens, I.

1999-01-01

The effects of changes in solar UV-B on the growth and pigmentation of six grass species from cold-temperate grasslands (Lolium perenne, Lolium multiflorum, Festuca arundinacea, Festuca rubra, Phleum pratense and Dactylis glomerata) in spring and summer were studied. The grasses were grown in greenhouses with different foils, resulting in three treatments: no UV-B, 80% of ambient and 90% of ambient UV-BBE (biologically effective UV-B). The results indicated important effects of ambient UV-B levels on grass, but the different species reacted in very different ways. Both morphology and biomass production were influenced by UV-B in some species. However, changes in biomass production did not necessarily occur within the same species as changes in morphology. The grasses were more sensitive in summer. Overall, only F. rubra was positively influenced by UV-B under all circumstances. The biomass of D. glomerata and L. perenne was reduced by UV-B in spring and summer. Morphological changes included reduced height and increased tillering. The sensitivity of the different species was partially explained by their ability to reduce their specific leaf area in response to UV-B. Only the more sensitive species showed increased production of protective pigments. Overall, there were important differences between the effect of a low level of UV-B, and the further increase in UV-B, indicating that several mechanisms are operating at different light levels. (author)

Degradation of Solar Array Components in a Combined UV/VUV High Temperature Test Environment

Directory of Open Access Journals (Sweden)

Nömayr Christel

2017-01-01

A design verification test under UV/VUV conditions of sun exposed materials and technologies on component level is presented which forms part of the overall verification and qualification of the solar array design of the MTM and MPO. The test concentrates on the self-contamination aspects and the resulting performance losses of the solar array under high intensity and elevated temperature environment representative for the photovoltaic assembly (PVA.

Electrostatic Discharge Test of Multi-Junction Solar Array Coupons After Combined Space Environmental Exposures

Science.gov (United States)

Wright, Kenneth H.; Schneider, Todd; Vaughn, Jason; Hoang, Bao; Funderburk, Victor V.; Wong, Frankie; Gardiner, George

2010-01-01

A set of multi-junction GaAs/Ge solar array test coupons were subjected to a sequence of 5-year increments of combined environmental exposure tests. The test coupons capture an integrated design intended for use in a geosynchronous (GEO) space environment. A key component of this test campaign is conducting electrostatic discharge (ESD) tests in the inverted gradient mode. The protocol of the ESD tests is based on the ISO/CD 11221, the ISO standard for ESD testing on solar array panels. This standard is currently in its final review with expected approval in 2010. The test schematic in the ISO reference has been modified with Space System/Loral designed circuitry to better simulate the on-orbit operational conditions of its solar array design. Part of the modified circuitry is to simulate a solar array panel coverglass flashover discharge. All solar array coupons used in the test campaign consist of 4 cells. The ESD tests are performed at the beginning of life (BOL) and at each 5-year environment exposure point. The environmental exposure sequence consists of UV radiation, electron/proton particle radiation, thermal cycling, and ion thruster plume. This paper discusses the coverglass flashover simulation, ESD test setup, and the importance of the electrical test design in simulating the on-orbit operational conditions. Results from 5th-year testing are compared to the baseline ESD characteristics determined at the BOL condition.

The total ozone and UV solar radiation over Stara Zagora, Bulgaria

Science.gov (United States)

Mendeva, B. D.; Gogosheva, Ts. N.; Petkov, B. H.; Krastev, D. G.

The results from direct ground-based solar UV irradiance measurements and the total ozone content (TOC) over Stara Zagora (42° 25'N, 25° 37'E), Bulgaria are presented. During the period 1999-2003 the TOC data show seasonal variations, typical for the middle latitudes - maximum in the spring and minimum in the autumn. The comparison between TOC ground-based data and Global Ozone Monitoring Experiment (GOME) satellite-borne ones shows a seasonal dependence of the differences between them. A strong negative relationship between the total ozone and the 305 nm wavelength irradiance was found. The dependence between the two variables is significant ( r = -0.62 ± 0.18) at 98% confidence level. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained. The estimation of the radiation amplification factor RAF shows that the ozone reduction by 1% increases the erythemal dose by 2.3%. The eye-damaging doses are more influenced by the TOC changes and in this case RAF = -2.7%. The amount of these biological doses depended on the solar altitude over the horizon. This dependence was not so strong when the total ozone content in the atmosphere was lower.

Solar UV radiation exposure of seamen - Measurements, calibration and model calculations of erythemal irradiance along ship routes

Energy Technology Data Exchange (ETDEWEB)

Feister, Uwe [German Meteorological Service, Meteorological Observatory Lindenberg - Richard-Assmann-Observatory, Am Observatorium 12, 15848 Lindenberg (Germany); Meyer, Gabriele; Kirst, Ulrich [German Social Accident Insurance Institution for Transport and Traffic, Ottenser Hauptstrasse 54, 22765 Hamburg (Germany)

2013-05-10

Seamen working on vessels that go along tropical and subtropical routes are at risk to receive high doses of solar erythemal radiation. Due to small solar zenith angles and low ozone values, UV index and erythemal dose are much higher than at mid-and high latitudes. UV index values at tropical and subtropical Oceans can exceed UVI = 20, which is more than double of typical mid-latitude UV index values. Daily erythemal dose can exceed the 30-fold of typical midlatitude winter values. Measurements of erythemal exposure of different body parts on seamen have been performed along 4 routes of merchant vessels. The data base has been extended by two years of continuous solar irradiance measurements taken on the mast top of RV METEOR. Radiative transfer model calculations for clear sky along the ship routes have been performed that use satellite-based input for ozone and aerosols to provide maximum erythemal irradiance and dose. The whole data base is intended to be used to derive individual erythemal exposure of seamen during work-time.

Morphological and physiological responses of two varieties of a highland species (Chenopodium quinoa Willd.) growing under near-ambient and strongly reduced solar UV-B in a lowland location.

Science.gov (United States)

González, Juan A; Rosa, Mariana; Parrado, María F; Hilal, Mirna; Prado, Fernando E

2009-08-03

Morphological and physiological responses of seedlings to different solar UV-B irradiances were evaluated in two varieties of quinoa (Chenopodium quinoa Willd.), a crop species from Andean region of South America. Cristalina and Chucapaca varieties were grown at 1965m a.s.l in a glasshouse under natural light conditions for 18 days, and then transferred to outdoors under near-ambient (+UV-B) and strongly reduced (-UV-B) solar UV-B radiation. Exposition to -UV-B increased cotyledon area and seedling height in Cristalina variety whereas leaf number decreased compared to +UV-B. By contrast Chucapaca variety was not affected by UV-B treatments. Seedling fresh weight (FW), root length and leaf thickness did not show significant differences between +UV-B and -UV-B treatments. Mesophyll tissue was slightly affected by solar UV-B reduction. Chlorophyll content was differentially affected by UV-B treatments. Under +UV-B the highest value was observed in Cristalina variety, while in Chucapaca it was observed under -UV-B treatment. Chlorophyll content was slightly higher in leaves than in cotyledons, but there was no difference in the distribution pattern. Chlorophyll a/b ratio and carotenoid content did not show significant differences between UV-B treatments. Leaf UVB-absorbing compounds showed significant differences between UV-B treatments in Chucapaca only, while there were no significant differences in Cristalina variety. UVB-absorbing compounds of cotyledons did not show significant differences between +UV-B and -UV-B treatments. Sucrose, glucose and fructose showed different distribution patterns in cotyledons and leaves of the two varieties under near-ambient and strongly reduced UV-B. Results demonstrated that varieties of quinoa exhibit different morphological and physiological responses to changes in solar UV-B irradiance, but these responses cannot be used to predict the sensitivity to solar UV-B during a short-term exposition. Also, this study can be useful to

Design of autotrack detecting instrument for solar UV radiation

Science.gov (United States)

Xia, Jiangtao; Mao, Xiaoli; Zhao, Jing

2009-11-01

In order to autotrack the object and detect the solar UV index, a reliable real-time high-precise instrument is proposed in this paper. This instrument involves two subsystems: the autotrack and detecting modules. The autotrack module consists of four-quadrant photo detector, multi-channel signal processing circuit and precise stepping system. The detecting module designed for dada measurement and acquisition is made up of the ultraviolet sensor UV460 and high precision A/D converter MAX1162. The key component of the entire instrument is ultralow-power microprocessor MSP430 which is used for entire system controlling and data processing. The lower system of autotracking and measurement is communicated with upper PC computer by RS232 module. In the experiment, the tracking precision of two-dimensional motion revolving stage is calibrated to be less than 0.05°. Experimental results indicate that the system designed could realize the precise autotracking and detecting function well, and the measure precision of system has reached the desirable target.

UV-induced skin damage

International Nuclear Information System (INIS)

Ichihashi, M.; Ueda, M.; Budiyanto, A.; Bito, T.; Oka, M.; Fukunaga, M.; Tsuru, K.; Horikawa, T.

2003-01-01

Solar radiation induces acute and chronic reactions in human and animal skin. Chronic repeated exposures are the primary cause of benign and malignant skin tumors, including malignant melanoma. Among types of solar radiation, ultraviolet B (290-320 nm) radiation is highly mutagenic and carcinogenic in animal experiments compared to ultraviolet A (320-400 nm) radiation. Epidemiological studies suggest that solar UV radiation is responsible for skin tumor development via gene mutations and immunosuppression, and possibly for photoaging. In this review, recent understanding of DNA damage caused by direct UV radiation and by indirect stress via reactive oxygen species (ROS) and DNA repair mechanisms, particularly nucleotide excision repair of human cells, are discussed. In addition, mutations induced by solar UV radiation in p53, ras and patched genes of non-melanoma skin cancer cells, and the role of ROS as both a promoter in UV-carcinogenesis and an inducer of UV-apoptosis, are described based primarily on the findings reported during the last decade. Furthermore, the effect of UV on immunological reaction in the skin is discussed. Finally, possible prevention of UV-induced skin cancer by feeding or topical use of antioxidants, such as polyphenols, vitamin C, and vitamin E, is discussed

Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase in marine macroalgae from southern Spain Efectos de la radiación solar UV sobre la fotosíntesis y actividades enzimáticas (anhidrasa carbónica y nitrato reductasa en macralgas marinas del sur de España

Directory of Open Access Journals (Sweden)

FÉLIX L. FIGUEROA

2001-06-01

nitrogen metabolism under solar radiation. Considering the absence of a significant correlation in U. rigida and the delay observed in maximal activities of P. cartilagineum in the absence of UV, it is suggested that UV radiation acts as an environmental signal involved in the control of cycles. The presence of feedback processes that control nitrogen assimilation as a function of carbon content is proposedEn este trabajo se presenta el efecto de la radiación solar ultravioleta (UV durante el ciclo diario de luz sobre la actividad fotosintética y la de dos enzimas claves en la incorporación de carbono, la anhidrasa carbónica, y en la reducción de nitrógeno inorgánico, la nitrato reductasa, en macroalgas del sur de España. Durante el ciclo diario de luz, la fotoinhibición, expresada como porcentaje de disminución del rendimiento cuántico efectivo desde la mañana al mediodía, estuvo linear y negativamente correlacionada con la irradiancia integrada diaria. Sin embargo, la recuperación, expresada como porcentaje de incremento del rendimiento cuántico efectivo desde el mediodía hasta el atardecer siguió un patrón diferente. Se observó recuperación completa a irradiancias integradas diarias menores a 1.0 x 10(4 kJ m-2. Sin embargo, a irradiancias diarias mayores, la recuperación fue sólo del 50 %. La existencia de fotoinhibición y de una recuperación diaria completa en macroalgas hace pensar que la fotoinhibición está funcionado como un mecanismo de fotoprotección contra radiaciones solares altas como ocurre en plantas terrestres. Además, los patrones de fotoinhición y recuperación tienen relación con la dosis acumulada diaria. Las actividades enzimáticas (anhidrasa carbónica y nitrato reductasa fueron determinadas en tres macroalgas marinas (Plocamium cartilagineum, Ulva rigida y Fucus spiralis bajo radiación solar completa (PAR + UV-A + UV-B y excluyendo la radiación UV (PAR. Bajo PAR + UV-A + UV-B se observó un máximo en la actividad de

Mid-latitude summer response of the middle atmosphere to short-term solar UV changes

Directory of Open Access Journals (Sweden)

P. Keckhut

1995-06-01

Full Text Available Temperature and wind data obtained with Rayleigh lidar since 1979 and Russian rockets since 1964 are analyzed to deduce the summer response of the middle atmosphere to short-term solar UV changes. The equivalent width of the 1083 nm He I line is used as a proxy to monitor the short-term UV flux changes. Spectral analyses are performed on 108-day windows to extract the 27-day component from temperature, wind and solar data sets. Linear regressions between these spectral harmonics show some significant correlations around 45 km at mid-latitudes. For large 27-day solar cycles, amplitudes of 2 K and 6 m s-1 are calculated for temperature data series over the south of France (44°N, and on wind data series over Volgograd (49°N, respectively. Cross-spectrum analyses have indicated correlations between these atmospheric parameters and the solar proxy with a phase lag of less than 2 days. These statistically correlative results, which provide good qualitative agreement with numerical simulations, are both obtained at mid-latitude. However, the observed amplitudes are larger than expected, with numerical models suggesting that dynamical processes such as equatorial or gravity waves may be responsible.

Mid-latitude summer response of the middle atmosphere to short-term solar UV changes

Directory of Open Access Journals (Sweden)

P. Keckhut

Full Text Available Temperature and wind data obtained with Rayleigh lidar since 1979 and Russian rockets since 1964 are analyzed to deduce the summer response of the middle atmosphere to short-term solar UV changes. The equivalent width of the 1083 nm He I line is used as a proxy to monitor the short-term UV flux changes. Spectral analyses are performed on 108-day windows to extract the 27-day component from temperature, wind and solar data sets. Linear regressions between these spectral harmonics show some significant correlations around 45 km at mid-latitudes. For large 27-day solar cycles, amplitudes of 2 K and 6 m s^-1 are calculated for temperature data series over the south of France (44°N, and on wind data series over Volgograd (49°N, respectively. Cross-spectrum analyses have indicated correlations between these atmospheric parameters and the solar proxy with a phase lag of less than 2 days. These statistically correlative results, which provide good qualitative agreement with numerical simulations, are both obtained at mid-latitude. However, the observed amplitudes are larger than expected, with numerical models suggesting that dynamical processes such as equatorial or gravity waves may be responsible.

Sacrificial hydrogen generation from aqueous triethanolamine with Eosin Y-sensitized Pt/TiO2 photocatalyst in UV, visible and solar light irradiation.

Science.gov (United States)

Chowdhury, Pankaj; Gomaa, Hassan; Ray, Ajay K

2015-02-01

In this paper, we have studied Eosin Y-sensitized sacrificial hydrogen generation with triethanolamine as electron donor in UV, visible, and solar light irradiation. Aeroxide TiO2 was loaded with platinum metal via solar photo-deposition method to reduce the electron hole recombination process. Photocatalytic sacrificial hydrogen generation was influenced by several factors such as platinum loading (wt%) on TiO2, solution pH, Eosin Y to Pt/TiO2 mass ratio, triethanolamine concentration, and light (UV, visible and solar) intensities. Detailed reaction mechanisms in visible and solar light irradiation were established. Oxidation of triethanolamine and formaldehyde formation was correlated with hydrogen generation in both visible and solar lights. Hydrogen generation kinetics followed a Langmuir-type isotherm with reaction rate constant and adsorption constant of 6.77×10(-6) mol min(-1) and 14.45 M(-1), respectively. Sacrificial hydrogen generation and charge recombination processes were studied as a function of light intensities. Apparent quantum yields (QYs) were compared for UV, visible, and solar light at four different light intensities. Highest QYs were attained at lower light intensity because of trivial charge recombination. At 30 mW cm(-2) we achieved QYs of 10.82%, 12.23% and 11.33% in UV, visible and solar light respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Autonomous portable solar ultraviolet spectroradiometer (APSUS) - a new CCD spectrometer system for localized, real-time solar ultraviolet (280-400 nm) radiation measurement.

Science.gov (United States)

Hooke, Rebecca; Pearson, Andy; O'Hagan, John

2014-01-01

Terrestrial solar ultraviolet (UV) radiation has significant implications for human health and increasing levels are a key concern regarding the impact of climate change. Monitoring solar UV radiation at the earth's surface is therefore of increasing importance. A new prototype portable CCD (charge-coupled device) spectrometer-based system has been developed that monitors UV radiation (280-400 nm) levels at the earth's surface. It has the ability to deliver this information to the public in real time. Since the instrument can operate autonomously, it is called the Autonomous Portable Solar Ultraviolet Spectroradiometer (APSUS). This instrument incorporates an Ocean Optics QE65000 spectrometer which is contained within a robust environmental housing. The APSUS system can gather reliable solar UV spectral data from approximately April to October inclusive (depending on ambient temperature) in the UK. In this study the new APSUS unit and APSUS system are presented. Example solar UV spectra and diurnal UV Index values as measured by the APSUS system in London and Weymouth in the UK in summer 2012 are shown. © 2014 Crown copyright. Photochemistry and Photobiology © 2014 The American Society of Photobiology. This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland and Public Health England.

Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

Science.gov (United States)

Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian

2016-03-01

Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

Environmental impacts from the solar energy technologies

International Nuclear Information System (INIS)

Tsoutsos, Theocharis; Frantzeskaki, Niki; Gekas, Vassilis

2005-01-01

Solar energy systems (photovoltaics, solar thermal, solar power) provide significant environmental benefits in comparison to the conventional energy sources, thus contributing, to the sustainable development of human activities. Sometimes however, their wide scale deployment has to face potential negative environmental implications. These potential problems seem to be a strong barrier for a further dissemination of these systems in some consumers. To cope with these problems this paper presents an overview of an Environmental Impact Assessment. We assess the potential environmental intrusions in order to ameliorate them with new technological innovations and good practices in the future power systems. The analysis provides the potential burdens to the environment, which include - during the construction, the installation and the demolition phases, as well as especially in the case of the central solar technologies - noise and visual intrusion, greenhouse gas emissions, water and soil pollution, energy consumption, labour accidents, impact on archaeological sites or on sensitive ecosystems, negative and positive socio-economic effects

MEASUREMENT OF SURFACE SOLAR UV-B RADIATION AT TROPICAL COASTAL STATION BAKKHALI IN WEST BENGAL, INDIA

OpenAIRE

R. BHATTACHARYA; A. BHOUMICK

2012-01-01

Surface solar ultraviolet irradiance has been measured at Bakkhali (21.8ºN, 87.8ºE), a tropical rural station on the coast of Bay of Bengal, India in West Bengal. The measurements show a remarkable variation in UV-B load exists with a peak value at noon. The blockage of direct UV radiation in mangrove forest of costal site appears low when compared with UV load beneath the multiple trees of Mangifera indica in an inland site of Kalyani (22058' N, 88028' E), West Bengal. Mangrove forests have ...

Solar UV-treatment of water samples for stripping-voltammetric determination of trace heavy metals in Awash river, Ethiopia

Directory of Open Access Journals (Sweden)

Gelaneh Woldemichael

2016-03-01

Full Text Available We report about testing a new mobile and sustainable water sample digestion method in a preliminary field trial in Ethiopia. In order to determine heavy metals at the ultra-trace level by stripping voltammetric techniques in water samples from Awash River, we applied our new method of solar UV-assisted sample pretreatment to destroy the relevant interfering dissolved organic matter. The field tests revealed that 24 h of solar UV irradiation were sufficient to achieve the same sample pretreatment results as with classic digestion method based on intense and hard UV. Analytical results of this study suggest that both a hydroelectric power station and agrichemical applications at Koka Lake have increased the levels of the investigated metals zinc, cadmium, lead, copper, cobalt, nickel, and uranium.

UV-A enhanced growth and UV-B induced positive effects in the recovery of photochemical yield in Gracilaria lemaneiformis (Rhodophyta).

Science.gov (United States)

Xu, Juntian; Gao, Kunshan

2010-09-02

The effects of solar UV radiation (280-400 nm) on growth, quantum yield and pigmentation in Gracilaria lemaneiformis were investigated when the thalli were cultured under solar radiation with or without UV for a period of 15 days. Presence of UV-A (315-400 nm) enhanced the relative growth rate, while UV-B (218-315 nm) inhibited it. The positive effect of UV-A and negative effect of UV-B counteracted to result in an insignificant impact of UVR on growth. During the noon period, both UV-A and UV-B resulted in the decrease of maximum quantum yield (Fv/Fm), but UV-B aided in the recovery of the yield in the late afternoon, reflecting that UV-B might be used as a signal in photorepair processes. UV induced the accumulation of UV-absorbing compounds (UVAC) to defend against the harmful UVR. However, the accumulation of UVAC took a much longer time compared to that previously reported, which was probably due to the lower levels of solar radiation and water temperature in the early spring period. Unknown UV-absorbing compounds (UVAC), which peaked at 265 nm, probably the precursor of MAAs (UVAC(325)), accumulated under moderate levels of solar radiation and were transformed to MAAs under higher solar radiation. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Beneficial effects of solar UV-B radiation on soybean yield mediated by reduced insect herbivory under field conditions.

Science.gov (United States)

Mazza, Carlos A; Giménez, Patricia I; Kantolic, Adriana G; Ballaré, Carlos L

2013-03-01

Ultraviolet-B radiation (UV-B: 280-315 nm) has damaging effects on cellular components and macromolecules. In plants, natural levels of UV-B can reduce leaf area expansion and growth, which can lead to reduced productivity and yield. UV-B can also have important effects on herbivorous insects. Owing to the successful implementation of the Montreal Protocol, current models predict that clear-sky levels of UV-B radiation will decline during this century in response to ozone recovery. However, because of climate change and changes in land use practices, future trends in UV doses are difficult to predict. In the experiments reported here, we used an exclusion approach to study the effects of solar UV-B radiation on soybean crops, which are extensively grown in many areas of the world that may be affected by future variations in UV-B radiation. In a first experiment, performed under normal management practices (which included chemical pest control), we found that natural levels of UV-B radiation reduced soybean yield. In a second experiment, where no pesticides were applied, we found that solar UV-B significantly reduced insect herbivory and, surprisingly, caused a concomitant increase in crop yield. Our data support the idea that UV-B effects on agroecosystems are the result of complex interactions involving multiple trophic levels. A better understanding of the mechanisms that mediate the anti-herbivore effect of UV-B radiation may be used to design crop varieties with improved adaptation to the cropping systems that are likely to prevail in the coming decades in response to agricultural intensification. Copyright © Physiologia Plantarum 2012.

Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

Directory of Open Access Journals (Sweden)

P. J. Nowack

2016-03-01

Full Text Available Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM. Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere–ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

Exposure of Finnish population to solar UV radiation and consequent carcinogenic effects

Energy Technology Data Exchange (ETDEWEB)

Huurto, L; Jansen, C [Turku Univ. Hospital, Turku (Finland); Jokela, K [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

1997-12-31

Depletion of stratospheric ozone increases irradiance of terrestrial ultraviolet (UV) radiation at short wavelengths, which may be harmful to the human health. To understand quantitatively the risks caused by increasing UV radiation to the Finnish population, the actual UV exposure of the population has to be assessed. It was shown that the snow reflection increases the UV exposure to the face and eyes particularly in the northern Finland. In 1993 exceptionally low ozone levels persisted up to the end of May, which resulted in a theoretical increase in the annual UV dose ranging from 8 % to 13 % in Finland. The maximal increase in the measured erythemally effective dose rate was 34 % on 23 April, when compared with the theoretical normal value. During this study exposure models have been developed. The models have been combined them with Green`s radiation transfer model to estimate annual facial UV doses received by different groups of Finnish population. Also, an updated estimate for increase in skin cancer incidence due to the ozone depletion is presented. It is estimated that the maximal increase in UV doses caused by the depletion of the stratospheric ozone will be 12 % in the first years of the next century in Finland. This may result in increase in skin carcinomas by 20-30 % if the people do not improve their protection against solar UV radiation. At the moment the annual facial UV dose of the Finnish indoor worker varies from 3 % to 6 % of the annual ambient dose. In the worst case an outdoor worker may receive even 16% of the annual ambient dose. However, the doses received by indoor workers during vacation to an untanned skin may be more harmful due to the increased risk of malignant melanoma.

Exposure of Finnish population to solar UV radiation and consequent carcinogenic effects

Energy Technology Data Exchange (ETDEWEB)

Huurto, L.; Jansen, C. [Turku Univ. Hospital, Turku (Finland); Jokela, K. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

1996-12-31

Depletion of stratospheric ozone increases irradiance of terrestrial ultraviolet (UV) radiation at short wavelengths, which may be harmful to the human health. To understand quantitatively the risks caused by increasing UV radiation to the Finnish population, the actual UV exposure of the population has to be assessed. It was shown that the snow reflection increases the UV exposure to the face and eyes particularly in the northern Finland. In 1993 exceptionally low ozone levels persisted up to the end of May, which resulted in a theoretical increase in the annual UV dose ranging from 8 % to 13 % in Finland. The maximal increase in the measured erythemally effective dose rate was 34 % on 23 April, when compared with the theoretical normal value. During this study exposure models have been developed. The models have been combined them with Green`s radiation transfer model to estimate annual facial UV doses received by different groups of Finnish population. Also, an updated estimate for increase in skin cancer incidence due to the ozone depletion is presented. It is estimated that the maximal increase in UV doses caused by the depletion of the stratospheric ozone will be 12 % in the first years of the next century in Finland. This may result in increase in skin carcinomas by 20-30 % if the people do not improve their protection against solar UV radiation. At the moment the annual facial UV dose of the Finnish indoor worker varies from 3 % to 6 % of the annual ambient dose. In the worst case an outdoor worker may receive even 16% of the annual ambient dose. However, the doses received by indoor workers during vacation to an untanned skin may be more harmful due to the increased risk of malignant melanoma.

In the shadow of the Cosmetic Directive — Inconsistencies in EU environmental hazard classification requirements for UV-filters

International Nuclear Information System (INIS)

Sobek, A.; Bejgarn, S.; Rudén, C.; Molander, L.; Breitholtz, M.

2013-01-01

UV-filters are chemicals with potentially environmental hazardous properties. In the European Union (EU), UV-filters contained in sunscreen products are currently regulated by the Cosmetic Directive (from July 2013 by the Cosmetic Products Regulation). Environmental hazard classifications according to the regulation on classification, labelling and packaging of substances and mixtures (CLP) must be determined for UV-filters contained in industrial chemical products, whereas UV-filters contained in sunscreens are exempted from CLP. In this study we determined the potential environmental hazard classifications of UV-filters and sunscreen products if the CLP regulation was to be required for cosmetic products. Two sunscreen products were evaluated in accordance with the aquatic environmental hazard criteria for mixtures. The results highlight that the inconsistencies in the current EU regulation of UV filters hamper the risk management of environmental hazards of UV filters used in cosmetic products. Almost 50% of the investigated UV-filters approved for use in cosmetic products on the European market according to the current Cosmetic Directive were identified to meet the CLP classification as being hazardous to the aquatic environment. Assuming a worst-case scenario, the two examined sunscreens could both be classified as hazardous to the aquatic environment with long-lasting effects according to CLP classification criteria. Hence, if the CLP regulation was applicable to sunscreen products, both brands could potentially be labelled with the environmental hazard pictogram and associated hazard and precautionary statements. Including cosmetic products, and thereby sunscreens, in the CLP regulation would contribute to a more harmonized and transparent regulation of potentially hazardous substances on the EU market. - Highlights: • UV-filters are used in both cosmetic and industrial products/applications • UV-filters in cosmetic products are excluded from CLP • We

Role of ultraviolet (UV) disinfection in infection control and environmental cleaning.

Science.gov (United States)

Qureshi, Zubair; Yassin, Mohamed H

2013-06-01

Ultraviolet (UV) radiation is capable of disinfecting surfaces, water and air. The UV technology was used for many years. However, safer and more effective delivery systems of UV radiation, make it a very useful option for disinfection. Effective disinfection of environmental surfaces is a key step in the prevention of spread of infectious agents. The traditional manual cleaning is essential in assuring adequate elimination of contamination. However, terminal cleaning is frequently suboptimal or unpredictable in many circumstances. UV-C radiation is an adjunctive disinfectant new technology that could kill a wide array of microorganisms including both vegetative and spore forming pathogens. The technology is getting more affordable and has produced consistent reproducible significant reduction of bacterial contamination.

Solar UV irradiances modulate effects of ocean acidification on the coccolithophorid Emiliania huxleyi.

Science.gov (United States)

Xu, Kai; Gao, Kunshan

2015-01-01

Emiliania huxleyi, the most abundant coccolithophorid in the oceans, is naturally exposed to solar UV radiation (UVR, 280-400 nm) in addition to photosynthetically active radiation (PAR). We investigated the physiological responses of E. huxleyi to the present day and elevated CO2 (390 vs 1000 μatm; with pH(NBS) 8.20 vs 7.86) under indoor constant PAR and fluctuating solar radiation with or without UVR. Enrichment of CO2 stimulated the production rate of particulate organic carbon (POC) under constant PAR, but led to unchanged POC production under incident fluctuating solar radiation. The production rates of particulate inorganic carbon (PIC) as well as PIC/POC ratios were reduced under the elevated CO2, ocean acidification (OA) condition, regardless of PAR levels, and the presence of UVR. However, moderate levels of UVR increased PIC production rates and PIC/POC ratios. OA treatment interacted with UVR to influence the alga's physiological performance, leading to reduced specific growth rate in the presence of UVA (315-400 nm) and decreased quantum yield, along with enhanced nonphotochemical quenching, with addition of UVB (280-315 nm). The results clearly indicate that UV radiation needs to be invoked as a key stressor when considering the impacts of ocean acidification on E. huxleyi. © 2014 The American Society of Photobiology.

The UV-A and visible solar irradiance spectrum: inter-comparison of absolutely calibrated, spectrally medium resolution solar irradiance spectra from balloon- and satellite-borne measurements

Directory of Open Access Journals (Sweden)

W. Gurlit

2005-01-01

Full Text Available Within the framework of the ENVISAT/-SCIAMACHY satellite validation, solar irradiance spectra are absolutely measured at moderate resolution in the UV/visible spectral range (in the UV from 316.7-418 nm and the visible from 400-652 nm at a full width half maximum resolution of 0.55 nm and 1.48 nm, respectively from aboard the azimuth-controlled LPMA/DOAS balloon gondola at around 32 km balloon float altitude. After accounting for the atmospheric extinction due to Rayleigh scattering and gaseous absorption (O3 and NO2, the measured solar spectra are compared with previous observations. Our solar irradiance spectrum perfectly agrees within +0.03% with the re-calibrated Kurucz et al. (1984 solar spectrum (Fontenla et al., 1999, called MODTRAN 3.7 in the visible spectral range (415-650 nm, but it is +2.1% larger in the (370-415 nm wavelength interval, and -4% smaller in the UV-A spectral range (316.7-370 nm, when the Kurucz spectrum is convolved to the spectral resolution of our instrument. Similar comparisons of the SOLSPEC (Thuillier et al., 1997, 1998a, b and SORCE/SIM (Harder et al., 2000 solar spectra with MODTRAN 3.7 confirms our findings with the values being -0.5%, +2%, and -1.4% for SOLSPEC -0.33%, -0.47%, and -6.2% for SORCE/SIM, respectively. Comparison of the SCIAMACHY solar spectrum from channels 1 to 4 (- re-calibrated by the University of Bremen - with MODTRAN 3.7 indicates an agreement within -0.4% in the visible spectral range (415-585 nm, -1.6% within the 370-415 nm, and -5.7% within 325-370 nm wavelength interval, in agreement with the results of the other sensors. In agreement with findings of Skupin et al. (2002 our study emphasizes that the present ESA SCIAMACHY level 1 calibration is systematically +15% larger in the considered wavelength intervals when compared to all available other solar irradiance measurements.

Ambient solar UV radiation and seasonal trends in potential sunburn risk among schoolchildren in South Africa

CSIR Research Space (South Africa)

Wright, CY

2011-07-01

Full Text Available The detrimental effects of excess personal solar ultraviolet (UV) radiation exposure include sunburn, immunosuppression and skin cancer. In South Africa, individuals with minimum natural protection from melanin, including fair-skinned individuals...

Alfalfa seedlings grown outdoors are more resistant to UV-induced DNA damage than plants grown in a UV-free environmental chamber

International Nuclear Information System (INIS)

Takayanagi, Shinnosuke; Trunk, J.G.; Sutherland, J.C.; Sutherland, B.M.

1994-01-01

The relative UV sensitivities of alfalfa seedlings grown outdoors versus plants grown in a growth chamber under UV-filtered cool white fluorescent bulbs have been determined using three criteria: (1) level of endogenous DNA damage as sites for the UV endonuclease from Micrococcus luteus, (2) susceptibility to pyrimidine dimer induction by a UV challenge exposure and (3) ability to repair UV-induced damage. We find that outdoor-grown plants contain approximately equal frequencies of endogenous DNA damages, are less susceptible to dimer induction by a challenge exposure of broad-spectrum UV and photorepair dimers more rapidly than plants grown in an environmental chamber under cool white fluorescent lamps plus a filter removes most UV radiation. These data suggest that plants grown in a natural environment would be less sensitive to UVB-induced damage than would be predicted on the basis of studies on plants grown under minimum UV. (author)

In the shadow of the Cosmetic Directive--inconsistencies in EU environmental hazard classification requirements for UV-filters.

Science.gov (United States)

Sobek, A; Bejgarn, S; Rudén, C; Molander, L; Breitholtz, M

2013-09-01

UV-filters are chemicals with potentially environmental hazardous properties. In the European Union (EU), UV-filters contained in sunscreen products are currently regulated by the Cosmetic Directive (from July 2013 by the Cosmetic Products Regulation). Environmental hazard classifications according to the regulation on classification, labelling and packaging of substances and mixtures (CLP) must be determined for UV-filters contained in industrial chemical products, whereas UV-filters contained in sunscreens are exempted from CLP. In this study we determined the potential environmental hazard classifications of UV-filters and sunscreen products if the CLP regulation was to be required for cosmetic products. Two sunscreen products were evaluated in accordance with the aquatic environmental hazard criteria for mixtures. The results highlight that the inconsistencies in the current EU regulation of UV filters hamper the risk management of environmental hazards of UV filters used in cosmetic products. Almost 50% of the investigated UV-filters approved for use in cosmetic products on the European market according to the current Cosmetic Directive were identified to meet the CLP classification as being hazardous to the aquatic environment. Assuming a worst-case scenario, the two examined sunscreens could both be classified as hazardous to the aquatic environment with long-lasting effects according to CLP classification criteria. Hence, if the CLP regulation was applicable to sunscreen products, both brands could potentially be labelled with the environmental hazard pictogram and associated hazard and precautionary statements. Including cosmetic products, and thereby sunscreens, in the CLP regulation would contribute to a more harmonized and transparent regulation of potentially hazardous substances on the EU market. Copyright © 2013 Elsevier B.V. All rights reserved.

Environmental and solar energy techniques

International Nuclear Information System (INIS)

Zaidi, Z.I.

2003-01-01

Technologies for fossil fuel extraction, transportation, processing and their use have harmful impact on the environment which cause direct and indirect negative impact on human heath, animals, crops and structure etc. The end use of all the fossil fuels is combustion irrespective of the final purpose i.e. heating, electricity production and motive power for transportation. The main constituents of fossil fuels are carbon and hydrogen but some other ingredients, which are originally in the fuel e.g. sulfur or are added during refining e.g. lead, alcohol etc. Combustion of the fossil fuel produces various gases (CO/sub x/, SO/sub x/ NO/sub x/, CH,), soot, ash, droplets of tar and other organic compounds, which are all released into the atmosphere. High rate of population growth and industrialization in the developing countries are causing unsustainable use of forest resources and fossil fuels, hence, are serious hurdles in environmental improvement. The situation in Pakistan is even worse as it has very limited fossil fuels and 40% of its commercial energy requirement are to be imported every year. Renewable energy technologies on the other hand, can play a vital role in improving the environmental condition globally. Pakistan Council of Renewable Energy Technologies (PCRET) is working in the field of renewable energy technologies. The Council has developed solar modules and solar thermal devices including solar cookers, solar dryers, solar stills and solar water heaters. The paper describes these devices and contribution they can make towards the improvement of environment. (author)

Multiple Roles for UV RESISTANCE LOCUS8 in Regulating Gene Expression and Metabolite Accumulation in Arabidopsis under Solar Ultraviolet Radiation1[W][OA

Science.gov (United States)

Morales, Luis O.; Brosché, Mikael; Vainonen, Julia; Jenkins, Gareth I.; Wargent, Jason J.; Sipari, Nina; Strid, Åke; Lindfors, Anders V.; Tegelberg, Riitta; Aphalo, Pedro J.

2013-01-01

Photomorphogenic responses triggered by low fluence rates of ultraviolet B radiation (UV-B; 280–315 nm) are mediated by the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8). Beyond our understanding of the molecular mechanisms of UV-B perception by UVR8, there is still limited information on how the UVR8 pathway functions under natural sunlight. Here, wild-type Arabidopsis (Arabidopsis thaliana) and the uvr8-2 mutant were used in an experiment outdoors where UV-A (315–400 nm) and UV-B irradiances were attenuated using plastic films. Gene expression, PYRIDOXINE BIOSYNTHESIS1 (PDX1) accumulation, and leaf metabolite signatures were analyzed. The results show that UVR8 is required for transcript accumulation of genes involved in UV protection, oxidative stress, hormone signal transduction, and defense against herbivores under solar UV. Under natural UV-A irradiance, UVR8 is likely to interact with UV-A/blue light signaling pathways to moderate UV-B-driven transcript and PDX1 accumulation. UVR8 both positively and negatively affects UV-A-regulated gene expression and metabolite accumulation but is required for the UV-B induction of phenolics. Moreover, UVR8-dependent UV-B acclimation during the early stages of plant development may enhance normal growth under long-term exposure to solar UV. PMID:23250626

The solar UV exposure time required for vitamin D3 synthesis in the human body estimated by numerical simulation and observation in Japan

Science.gov (United States)

Nakajima, Hideaki; Miyauchi, Masaatsu; Hirai, Chizuko

2013-04-01

After the discovery of Antarctic ozone hole, the negative effect of exposure of human body to harmful solar ultraviolet (UV) radiation is widely known. However, there is positive effect of exposure to UV radiation, i.e., vitamin D synthesis. Although the importance of solar UV radiation for vitamin D3 synthesis in the human body is well known, the solar exposure time required to prevent vitamin D deficiency has not been well determined. This study attempted to identify the time of solar exposure required for vitamin D3 synthesis in the body by season, time of day, and geographic location (Sapporo, Tsukuba, and Naha, in Japan) using both numerical simulations and observations. According to the numerical simulation for Tsukuba at noon in July under a cloudless sky, 2.3 min of solar exposure are required to produce 5.5 μg vitamin D3 per 600 cm2 skin. This quantity of vitamin D represents the recommended intake for an adult by the Ministry of Health, Labour and Welfare, and the 2010 Japanese Dietary Reference Intakes (DRIs). In contrast, it took 49.5 min to produce the same amount of vitamin D3 at Sapporo in the northern part of Japan in December, at noon under a cloudless sky. The necessary exposure time varied considerably with the time of the day. For Tsukuba at noon in December, 14.5 min were required, but at 09:00 68.7 min were required and at 15:00 175.8 min were required for the same meteorological conditions. Naha receives high levels of UV radiation allowing vitamin D3 synthesis almost throughout the year. According to our results, we are further developing an index to quantify the necessary time of UV radiation exposure to produce required amount of vitamin D3 from a UV radiation data.

Protein Kinases and Transcription Factors Activation in Response to UV-Radiation of Skin: Implications for Carcinogenesis

OpenAIRE

Laurence A. Marchat; Elena Aréchaga Ocampo; Mavil López Casamichana; Carlos Pérez-Plasencia; César López-Camarillo; Elizbeth Álvarez-Sánchez

2011-01-01

Solar ultraviolet (UV) radiation is an important environmental factor that leads to immune suppression, inflammation, photoaging, and skin carcinogenesis. Here, we reviewed the specific signal transduction pathways and transcription factors involved in the cellular response to UV-irradiation. Increasing experimental data supporting a role for p38, MAPK, JNK, ERK1/2, and ATM kinases in the response network to UV exposure is discussed. We also reviewed the participation of NF-?B, AP-1, and NRF2...

Solar UV-assisted sample preparation of river water for ultra-trace determination of uranium by adsorptive stripping voltammetry

International Nuclear Information System (INIS)

Woldemichael, G.; Tulu, T.; Flechsig, G.-U.

2012-01-01

The article describes how solar ultraviolet-A radiation can be used to digest samples as needed for voltammetric ultratrace determination of uranium(VI) in river water. We applied adsorptive stripping voltammetry (AdSV) using chloranilic acid as the complexing agent. Samples from the river Warnow in Rostock (Germany) were pretreated with either soft solar UV or wit artificial hard UV from a 30-W source emitting 254-nm light. Samples were irradiated for 12 h, and both methods yielded the same results. We were able to detect around 1 μg.L -1 of uranium(VI) in a sample of river water that also contained dissolved organic carbon at a higher mg.L -1 levels. No AdSV signal was obtained for U(VI) without any UV pre-treatment. Pseudo-polarographic experiments confirmed the dramatic effect of both digestion techniques the the AdSV response. The new method is recommended for use in mobile ultratrace voltammetry of heavy metals for most kinds of natural water samples including tap, spring, ground, sea, and river waters. The direct use of solar radiation for sample pre-treatment represents a sustainable technique for sample preparation that does not consume large quantities of chemicals or energy. (author)

77 FR 4334 - Proposed Collection; Comment Request; Solar Cell: A Mobile UV Manager for Smart Phones (NCI)

Science.gov (United States)

2012-01-27

... DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Proposed Collection; Comment Request; Solar Cell: A Mobile UV Manager for Smart Phones (NCI) SUMMARY: In compliance with the... Manager for Smart Phones [[Page 4335

Implementation of innovative pulsed xenon ultraviolet (PX-UV environmental cleaning in an acute care hospital

Directory of Open Access Journals (Sweden)

Fornwalt L

2014-01-01

Full Text Available Lori Fornwalt,1 Brad Riddell1,2 1Departments of Infection Prevention and Environmental Services, Trinity Medical Centre, Birmingham, AL, 2Environmental Services, Medical University of South Carolina, Charleston, SC, USA Abstract: It is widely acknowledged that the hospital environment is an important reservoir for many of the pathogenic microbes associated with health care-associated infections (HAIs. Environmental cleaning plays an important role in the prevention and containment of HAIs, in patient safety, and the overall experience of health care facilities. New technologies, such as pulsed xenon ultraviolet (PX-UV light systems are an innovative development for enhanced cleaning and decontamination of hospital environments. A portable PX-UV disinfection device delivers pulsed UV light to destroy microbial pathogens and spores, and can be used in conjunction with manual environmental cleaning. In addition, this technology facilitates thorough disinfection of hospital rooms in 10–15 minutes. The current study was conducted to evaluate whether the introduction of the PX-UV device had a positive impact on patient satisfaction. Satisfaction was measured using the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS survey. In 2011, prior to the introduction of the PX-UV system, patient HCAHPS scores for cleanliness averaged 75.75%. In the first full quarter after enhanced cleaning of the facility was introduced, this improved to 83%. Overall scores for the hospital rose from 76% (first quarter, 2011 to 87.6% (fourth quarter, 2012. As a result of this improvement, the hospital received 1% of at-risk reimbursement from the inpatient prospective payment system as well as additional funding. Cleanliness of the hospital environment is one of the questions included in the HCAHPS survey and one measure of patient satisfaction. After the introduction of the PX-UV system, the score for cleanliness and the overall rating of the

Duality of solar UV-B radiation and relevant dosimetry: vitamin D synthesis versus skin erythema

Science.gov (United States)

Terenetskaya, Irina P.

2003-06-01

Solar ultraviolet radiation (UVR) gives rise to beneficial or adverse health effects depending on the dose. Excessive UV exposures are associated with acute and chronic health effect but in appropriate doses UV sunlight is advisable. Important biological function of UVR is initiation of endogenous synthesis of vitamin D in human skin. A useful method based on an in vitro model of vitamin D synthesis ('D-dosimeter') has been specially developed to measure the vitamin D synthetic capacity of sunlight in situ. For the first time laboratory and field tests have been performed to link commonly used erythemal units (MEDs) and previtamin D accumulation.

The UV Sensor Onboard the Mars Science Laboratory Mission: Correction and Generation of UV Fluxes

Science.gov (United States)

Vicente-Retortillo, Á.; Martinez, G.; Renno, N. O.; Lemmon, M. T.; Gomez-Elvira, J.

2017-12-01

The Rover Environmental Monitoring Station UV sensor (UVS) onboard the Mars Science Laboratory mission has completed more than 1750 sols of measurements, providing an unprecedented coverage ranging from diurnal to interannual times scales [1,2]. The UVS is comprised of six photodiodes to measure the UV flux in the ranges 200-380, 320-380, 280-320, 200-280, 230-290 and 300-350 nm [3]. UV fluxes in units of W/m2 can be found in the NASA Planetary Data System (PDS). However, dust deposition on the UVS and a non-physical discontinuity in the calibration functions when the solar zenith angle is above 30º cause errors in these fluxes that increase with time. We have developed a technique to correct UV fluxes from the effects of dust degradation and inconsistencies in the angular response of the UVS. The photodiode output currents (available in the PDS as lower-level TELRDR products), ancillary data records (available in the PDS as ADR products) and dust opacity values derived from Mastcam observations are used for performing the corrections. The corrections have been applied to the UVA band (320-380 nm) for the first 1000 sols of the mission, providing excellent results [4]. We plan to correct the UV fluxes on each of the six UVS bands and to make these results available in the PDS. Data products generated by this study will allow comparisons of the UV radiation environment at Gale crater with that at the locations of the future missions ExoMars 2020 and Mars 2020, as well as the assessment of the potential survivability of biological contaminants brought to Mars from Earth. References: [1] Smith, M. D., et al. (2016), Aerosol optical depth as observed by the Mars Science Laboratory REMS UV photodiodes, Icarus, 280, 234-248. [2] Vicente-Retortillo, Á., et al. (2017), Determination of dust aerosol particle size at Gale Crater using REMS UVS and Mastcam measurements, Geophys. Res. Lett., 44, 3502-3508. [3] Gómez-Elvira, J., et al. (2012), REMS: The environmental sensor

Solar UV-radiation, vitamin D and skin cancer surveillance in organ transplant recipients (OTRs).

Science.gov (United States)

Reichrath, Jörg; Nürnberg, Bernd

2008-01-01

The introduction of organ transplantation in clinical medicine has resulted in a constantly increasing, large population of patients that are chronically on immunosuppressive medication. It is well known that skin cancer, especially SCC, in this population has higher incidence rates, behaves more aggressively and has higher rates of metastasis. OTRs who have been treated for many years with immunosuppressive medication are at the highest risk for developing malignant skin tumors. Therefore, the intensity of surveillance for cutaneous lesions is of high importance in OTRs. A full-body skin exam at least once a year and more frequently if skin cancer or precancerous cutaneous lesions develop is recommended. Clinicians should not hesitate to biopsy or to surgically excise any suspicious skin lesion. Of high importance is also the education of OTRs about their increased risk. Protection against solar and artificial UV-radiation and monthly self-examinations are good ways to prevent and to recognize any new suspicious skin lesions. Patients are advised to always wear solar UV-radiation protection (e.g., clothing, sunscreen) before going outdoors. However, investigations have revealed that solar UV-B-exposure and serum 25(OH)D levels positively correlate with decreased risk for various internal malignancies (e.g., breast, colon, prostate and ovarian cancer) and other severe diseases. As we have shown previously, renal transplant recipients are at high risk of vitamin D deficiency. A sunscreen with a sun protection factor (SPF)-8 reduces the skin's production of vitamin D by 95%. Clothing completely blocks all solar UVB-radiation and this prevents any vitamin D production. Therefore, it is important to detect and treat vitamin D deficiency in solid organ transplant recipients. Optimal management of these patients requires communication between the transplant teams and the treating dermatologist and other clinicians. For advanced or metastatic disease, collaboration

Biological Sensors for Solar Ultraviolet Radiation

Directory of Open Access Journals (Sweden)

André P. Schuch

2011-04-01

Full Text Available Solar ultraviolet (UV radiation is widely known as a genotoxic environmental agent that affects Earth ecosystems and the human population. As a primary consequence of the stratospheric ozone layer depletion observed over the last decades, the increasing UV incidence levels have heightened the concern regarding deleterious consequences affecting both the biosphere and humans, thereby leading to an increase in scientific efforts to understand the role of sunlight in the induction of DNA damage, mutagenesis, and cell death. In fact, the various UV-wavelengths evoke characteristic biological impacts that greatly depend on light absorption of biomolecules, especially DNA, in living organisms, thereby justifying the increasing importance of developing biological sensors for monitoring the harmful impact of solar UV radiation under various environmental conditions. In this review, several types of biosensors proposed for laboratory and field application, that measure the biological effects of the UV component of sunlight, are described. Basically, the applicability of sensors based on DNA, bacteria or even mammalian cells are presented and compared. Data are also presented showing that on using DNA-based sensors, the various types of damage produced differ when this molecule is exposed in either an aqueous buffer or a dry solution. Apart from the data thus generated, the development of novel biosensors could help in evaluating the biological effects of sunlight on the environment. They also emerge as alternative tools for using live animals in the search for protective sunscreen products.

Exposure to Non-Extreme Solar UV Daylight: Spectral Characterization, Effects on Skin and Photoprotection

Directory of Open Access Journals (Sweden)

Claire Marionnet

2014-12-01

Full Text Available The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV rays (UVA, 320–400 nm and UVB, 280–320 nm. The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1 the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2 description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3 analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

Exposure to non-extreme solar UV daylight: spectral characterization, effects on skin and photoprotection.

Science.gov (United States)

Marionnet, Claire; Tricaud, Caroline; Bernerd, Françoise

2014-12-23

The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320-400 nm and UVB, 280-320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1) the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2) description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3) analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

Effect of UV irradiations on the structural and optical features of porous silicon: application in silicon solar cells

International Nuclear Information System (INIS)

Aouida, S.; Saadoun, M.; Boujmil, M.F.; Ben Rabha, M.; Bessaies, B.

2004-01-01

The aim of this paper is to investigate the structural and optical stability of porous silicon layers (PSLs) planned to be used in silicon solar cells technology. The PSLs were prepared by a HNO 3 /HF vapor etching (VE) based method. Fourier transform infrared (FT-IR) spectroscopy shows that fresh VE-based PSLs contain N-H and Si-F bonds related to a ammonium hexafluorosilicate (NH 4 ) 2 SiF 6 minor phase, and conventional Si-H x and Si-O x bonds. Free air exposures of PSLs without and with UV irradiation lead to oxidation or photo-oxidation of the porous layer, respectively. FT-IR characterisation of the PSLs shows that UV irradiations modify the transformation kinetics replacing instable Si-H x by Si-O x or Si-O-H bonds. When fresh PSLs undergo free air oxidation within 7 days, the surface reflectivity decreases from 10 to about 8%, while it drops to about 4% when a 10 min free air UV irradiation is applied. Long periods of free air oxidation do not ensure the reflectivity to be stable, whereas it becomes stable after only 10 min of UV irradiation. This behaviour was explained taking into account the kinetic differences between oxidation with and without UV irradiation. Fresh VE-based PSLs were found to improve efficiently the photovoltaic (PV) characteristics of crystalline silicon solar cells. The passivating action of VE-based PSLs was discussed. An improvement of the PV performances was observed solely for stable oxidized porous silicon (PS) structures obtained from UV irradiations

Enhanced charge transport and photovoltaic performance of PBDTTT-C-T/PC70BM solar cells via UV-ozone treatment.

Science.gov (United States)

Adhikary, Prajwal; Venkatesan, Swaminathan; Adhikari, Nirmal; Maharjan, Purna P; Adebanjo, Olusegun; Chen, Jihua; Qiao, Qiquan

2013-10-21

In this work, the electron transport layer of PBDTTT-C-T/PC70BM polymer solar cells were subjected to UV-ozone treatment, leading to improved cell performances from 6.46% to 8.34%. The solar cell efficiency reached a maximum of 8.34% after an optimal 5 minute UV-ozone treatment, and then decreased if treated for a longer time. To the best of our knowledge, the mechanism behind the effects of UV-ozone treatment on the improvement of charge transport and cell performance is not fully understood. We have developed a fundamental understanding of the UV-ozone treatment mechanism, which explains both the enhancements in charge transport and photovoltaic performance at an optimal treatment time, and also the phenomenon whereby further treatment time leads to a drop in cell efficiency. Transient photocurrent measurements indicated that the cell charge transport times were 1370 ns, 770 ns, 832 ns, 867 ns, and 1150 ns for the 0 min, 5 min, 10 min, 15 min, and 20 min UV-ozone treatment times, respectively. Therefore the 5 min UV-ozone treatment time led to the shortest transport time and the most efficient charge transport in the cells. The 5 min UV-ozone treated sample exhibited the highest peak intensity (E2) in the Raman spectra of the treated films, at about 437 cm(-1), indicating that it possessed the best wurtzite phase crystallinity of the ZnO films. Further increasing the UV-ozone treatment time from 5 to 20 min induced the formation of p-type defects (e.g. interstitial oxygen atoms), pushing the ZnO Fermi-level further away from the vacuum level, and decreasing the wurtzite crystallinity.

Environmental occurrence and distribution of organic UV stabilizers and UV filters in the sediment of Chinese Bohai and Yellow Seas.

Science.gov (United States)

Apel, Christina; Tang, Jianhui; Ebinghaus, Ralf

2018-04-01

Organic UV stabilizers and UV filters are applied to industrial materials and cosmetics worldwide. In plastics they prevent photo-induced degradation, while in cosmetics they protect human skin against harmful effects of UV radiation. This study reports on the occurrence and distribution of organic UV stabilizers and UV filters in the surface sediment of the Chinese Bohai and Yellow Seas for the first time. In total, 16 out of 21 analyzed substances were positively detected. Concentrations ranged from sub-ng/g dw to low ng/g dw. The highest concentration of 25 ng/g dw was found for octocrylene (OC) in the Laizhou Bay. In the study area, characteristic composition profiles could be identified. In Korea Bay, the dominating substances were OC and ethylhexyl salicylate (EHS). All other analytes were below their method quantification limit (MQL). Around the Shandong Peninsula, highest concentrations of benzotriazole derivatives were observed in this study with octrizole (UV-329) as the predominant compound, reaching concentrations of 6.09 ng/g dw. The distribution pattern of UV-329 and bumetrizole (UV-326) were related (Pearson correlation coefficient r > 0.98, p « 0.01 around the Shandong Peninsula), indicating an identical input pathway and similar environmental behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environmental impacts of utility-scale solar energy

Science.gov (United States)

Hernandez, R.R.; Easter, S.B.; Murphy-Mariscal, M. L.; Maestre, F.T.; Tavassoli, M.; Allen, E.B.; Barrows, C.W.; Belnap, J.; Ochoa-Hueso, R.; Ravi, S.; Allen, M.F.

2014-01-01

Renewable energy is a promising alternative to fossil fuel-based energy, but its development can require a complex set of environmental tradeoffs. A recent increase in solar energy systems, especially large, centralized installations, underscores the urgency of understanding their environmental interactions. Synthesizing literature across numerous disciplines, we review direct and indirect environmental impacts – both beneficial and adverse – of utility-scale solar energy (USSE) development, including impacts on biodiversity, land-use and land-cover change, soils, water resources, and human health. Additionally, we review feedbacks between USSE infrastructure and land-atmosphere interactions and the potential for USSE systems to mitigate climate change. Several characteristics and development strategies of USSE systems have low environmental impacts relative to other energy systems, including other renewables. We show opportunities to increase USSE environmental co-benefits, the permitting and regulatory constraints and opportunities of USSE, and highlight future research directions to better understand the nexus between USSE and the environment. Increasing the environmental compatibility of USSE systems will maximize the efficacy of this key renewable energy source in mitigating climatic and global environmental change.

A method for optimizing the cosine response of solar UV diffusers

Science.gov (United States)

Pulli, Tomi; Kärhä, Petri; Ikonen, Erkki

2013-07-01

Instruments measuring global solar ultraviolet (UV) irradiance at the surface of the Earth need to collect radiation from the entire hemisphere. Entrance optics with angular response as close as possible to the ideal cosine response are necessary to perform these measurements accurately. Typically, the cosine response is obtained using a transmitting diffuser. We have developed an efficient method based on a Monte Carlo algorithm to simulate radiation transport in the solar UV diffuser assembly. The algorithm takes into account propagation, absorption, and scattering of the radiation inside the diffuser material. The effects of the inner sidewalls of the diffuser housing, the shadow ring, and the protective weather dome are also accounted for. The software implementation of the algorithm is highly optimized: a simulation of 109 photons takes approximately 10 to 15 min to complete on a typical high-end PC. The results of the simulations agree well with the measured angular responses, indicating that the algorithm can be used to guide the diffuser design process. Cost savings can be obtained when simulations are carried out before diffuser fabrication as compared to a purely trial-and-error-based diffuser optimization. The algorithm was used to optimize two types of detectors, one with a planar diffuser and the other with a spherically shaped diffuser. The integrated cosine errors—which indicate the relative measurement error caused by the nonideal angular response under isotropic sky radiance—of these two detectors were calculated to be f2=1.4% and 0.66%, respectively.

UV-indeks og dets betydning

DEFF Research Database (Denmark)

Wulf, Hans Christian; Eriksen, Paul

2010-01-01

The published UV index refers to the expected UV intensity at mid day, when the solar elevation is at its maximum. In Scandinavia, the maximum UV index is seven around midsummer. When the UV index is three, the erythema-weighted dose will be three Standard Erythema Dose (SED) in the hour with max...... a sunburn already when the UV index is higher than two....

Exclusion of UV-B radiation from normal solar spectrum on the growth of mung bean and maize

International Nuclear Information System (INIS)

Pal, M.; Sharma, A.; Abrol, Y.P.; Sengupta, U.K.

1997-01-01

The increase in UV-B radiation due to depletion of the ozone layer has potentially harmful effects on plant growth and performance. The bulk of these studies conducted in growth chambers, greenhouses or in the field use different types of exposure systems which may be responsible for differences in the sensitivity of a crop to UV-B radiation. A field study using selective filters to remove the UV-B portion of the solar spectrum was conducted with mung bean (a dicotyledonous C 3 plant) and maize (a monocotyledonous C 4 plant) to determine the sensitivity of these crop plants to ambient UV-B levels without disturbing the microenvironment. Mung bean was found to be sensitive to ambient UV-B levels in terms of leaf area development, plant height attained and net photosynthesis, while maize was found to be unaffected by ambient UV-B levels (22.8 |GmW cm −2 nm −1 ) found in Delhi, India (28°38′N, 77°13′E). The level of ambient UV-B radiation thus appears to be inhibitory for optimal growth of plants, especially dicotyledonous mung bean. (author)

Ecological responses to UV radiation: interactions between the biological effects of UV on plants and on associated organisms.

Science.gov (United States)

Paul, Nigel D; Moore, Jason P; McPherson, Martin; Lambourne, Cathryn; Croft, Patricia; Heaton, Joanna C; Wargent, Jason J

2012-08-01

Solar ultraviolet (UV)-B radiation (280-315 nm) has a wide range of effects on terrestrial ecosystems, yet our understanding of how UV-B influences the complex interactions of plants with pest, pathogen and related microorganisms remains limited. Here, we report the results of a series of experiments in Lactuca sativa which aimed to characterize not only key plant responses to UV radiation in a field environment but also consequential effects for plant interactions with a sap-feeding insect, two model plant pathogens and phylloplane microorganism populations. Three spectrally modifying filters with contrasting UV transmissions were used to filter ambient sunlight, and when compared with our UV-inclusive filter, L. sativa plants grown in a zero UV-B environment showed significantly increased shoot fresh weight, reduced foliar pigment concentrations and suppressed population growth of green peach aphid (Myzus persicae). Plants grown under a filter which allowed partial transmission of UV-A radiation and negligible UV-B transmission showed increased density of leaf surface phylloplane microbes compared with the UV-inclusive treatment. Effects of UV treatment on the severity of two plant pathogens, Bremia lactucae and Botrytis cinerea, were complex as both the UV-inclusive and zero UV-B filters reduced the severity of pathogen persistence. These results are discussed with reference to known spectral responses of plants, insects and microorganisms, and contrasted with established fundamental responses of plants and other organisms to solar UV radiation, with particular emphasis on the need for future integration between different experimental approaches when investigating the effects of solar UV radiation. Copyright © Physiologia Plantarum 2011.

A review on the degradation of organic pollutants in waters by UV photoelectro-Fenton and solar photoelectro-Fenton

OpenAIRE

Brillas, Enric

2014-01-01

This paper presents a review on emerging electrochemical advanced oxidation processes (EAOPs) such as UV photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF) in which the irradiation of the effluent with UV light and sunlight, respectively, causes a synergistic effect on the degradation process of organic pollutants by the formation of more •OH and/or the photolysis of complexes of Fe(III) with generated carboxylic acids. Fundamentals of these EAOPs are explained to clarify their pe...

Comets in UV

Science.gov (United States)

Shustov, B.; Sachkov, M.; Gómez de Castro, A. I.; Vallejo, J. C.; Kanev, E.; Dorofeeva, V.

2018-04-01

Comets are important "eyewitnesses" of Solar System formation and evolution. Important tests to determine the chemical composition and to study the physical processes in cometary nuclei and coma need data in the UV range of the electromagnetic spectrum. Comprehensive and complete studies require additional ground-based observations and in situ experiments. We briefly review observations of comets in the ultraviolet (UV) and discuss the prospects of UV observations of comets and exocomets with space-borne instruments. A special reference is made to the World Space Observatory-Ultraviolet (WSO-UV) project.

77 FR 2734 - Proposed Collection; Comment Request: Solar Cell: A Mobile UV Manager for Smart Phones (NCI)

Science.gov (United States)

2012-01-19

... DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Proposed Collection; Comment Request: Solar Cell: A Mobile UV Manager for Smart Phones (NCI) SUMMARY: In compliance with the... Manager for Smart Phones (NCI). Type of Information Collection Request: New. Need and Use of Information...

Space Environmental Effects on Candidate Solar Sail Materials

Science.gov (United States)

Edwards, David L.; Nehls, Mary; Semmel, Charles; Hovater, Mary; Gray, Perry; Hubbs, Whitney; Wertz, George

2004-01-01

The National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) continues research into the utilization of photonic materials for spacecraft propulsion. Spacecraft propulsion, using photonic materials, will be achieved using a solar sail. A solar sail operates on the principle that photons, originating from the sun, impart pressure to the sail and therefore provide a source for spacecraft propulsion. The pressure imparted ot a solar sail can be increased, up to a factor of two, if the sun-facing surface is perfectly reflective. Therefore, these solar sails are generally composed of a highly reflective metallic sun-facing layer, a thin polymeric substrate and occasionally a highly emissive back surface. Near term solar sail propelled science missions are targeting the Lagrange point 1 (L1) as well as locations sunward of L1 as destinations. These near term missions include the Solar Polar Imager and the L1 Diamond. The Environmental Effects Group at NASA's Marshall Space Flight Center (MSFC) continues to actively characterize solar sail material in preparation for these near term solar sail missions. Previous investigations indicated that space environmental effects on sail material thermo-optical properties were minimal and would not significantly affect the propulsion efficiency of the sail. These investigations also indicated that the sail material mechanical stability degrades with increasing radiation exposure. This paper will further quantify the effect of space environmental exposure on the mechanical properties of candidate sail materials. Candidate sail materials for these missions include Aluminum coated Mylar, Teonex, and CP1 (Colorless Polyimide). These materials were subjected to uniform radiation doses of electrons and protons in individual exposures sequences. Dose values ranged from 100 Mrads to over 5 Grads. The engineering performance property responses of thermo-optical and mechanical properties were characterized

Utilising shade to optimize UV exposure for vitamin D

Science.gov (United States)

Turnbull, D. J.; Parisi, A. V.

2008-06-01

Numerous studies have stated that humans need to utilise full sun radiation, at certain times of the day, to assist the body in synthesising the required levels of vitamin D3. The time needed to be spent in the full sun depends on a number of factors, for example, age, skin type, latitude, solar zenith angle. Current Australian guidelines suggest exposure to approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on age, would be appropriate to provide adequate vitamin D3 levels. The aim of the study was to determine the exposure times to diffuse solar UV to receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in order to assess the possible role that diffuse UV (scattered radiation) may play in vitamin D3 effective UV exposures (UVD3). Diffuse and global erythemal UV measurements were conducted at five minute intervals over a twelve month period for a solar zenith angle range of 4° to 80° at a latitude of 27.6° S. For a diffuse UV exposure of 1/3 MED, solar zenith angles smaller than approximately 50° can be utilised for exposure times of less than 10 min. Spectral measurements showed that, for a solar zenith angle of 40°, the UVA (315-400 nm) in the diffuse component of the solar UV is reduced by approximately 62% compared to the UVA in the global UV, whereas UVD3 wavelengths are only reduced by approximately 43%. At certain latitudes, diffuse UV under shade may play an important role in providing the human body with adequate levels of UVD3 (290-315 nm) radiation without experiencing the high levels of UVA observed in full sun.

Validation and in vivo assessment of an innovative satellite-based solar UV dosimeter for a mobile app dedicated to skin health.

Science.gov (United States)

Morelli, M; Masini, A; Simeone, E; Khazova, M

2016-08-31

We present an innovative satellite-based solar UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in vivo assessment of the erythemal effects on some volunteers having controlled exposure to solar radiation. The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. Both validations showed that the system has a good accuracy and reliability needed for health-related applications. This app will be launched on the market by siHealth Ltd in May 2016 under the name of "HappySun" and is available for both Android and iOS devices (more info on ). Extensive R&D activities are on-going for the further improvement of the satellite-based UV dosimeter's accuracy.

A study on the relationship between incoming solar UV radiation and cloud cover

International Nuclear Information System (INIS)

Daoo, V.J.

1992-01-01

In this study an empirical relationship between the incoming solar UV radiation and concurrently measured cloud cover at Bombay (19 o 01'N, 72 o 55'E), based on data pertaining to two year (1986-1987) period is established. It is compared with a similar relationship used elsewhere and found to differ in its form as well as in the regression coefficients. Possible reasons for this discrepancy are discussed. Conditions under which the two relationships agree are also examined. (author)

Environmental aspects of the use of materials for solar water heaters

International Nuclear Information System (INIS)

Van der Leun, C.J.; De Jager, D.

1994-10-01

The study on the title subject has been carried out in order to apply the results in new designs and to improve the production of solar water heating systems. Attention is paid to solar water heaters that are under development and solar water heaters that are commercially available in the Netherlands. Use has been made of a IVAM-developed product analysis method. For seven solar water heater concepts, that were on the market or under development in the Netherlands in 1992, the applied amounts of materials have been inventorized. Data on the environmental effects of the production of these materials are outlined and aggregated on the level of the components and the systems. Based on those data, environmental profiles are drafted, comprising 'effect scores' on 9 environmental criteria. However, the environmental 'effect scores' are not reliable enough to determine the most important factors in order to identify options to reduce the negative environmental effects. Data on the energy consumption of the production of relevant materials are available and reliable. The solar water heaters, considered in this report, do not show large differences for that matter. It appears that the amounts of air pollution, water pollution and waste flow from the production of materials for solar water heaters are no reasons to further reduce environmental effects of the production. It is recommended to focus on the reduction of material quantities and to increase the quantity of recycled material. Also it is recommended that manufacturers of solar boilers set up a take-back system. 43 tabs., 1 appendix, 56 refs

UV-induced N2O emission from plants

DEFF Research Database (Denmark)

Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

2014-01-01

investigate for the fi rst time N 2 O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted fi eld site measurements to investigate N 2 O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory...... magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N 2 O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process...

UV dependent vitamin D syntheses. UV exposure time balancing for optimum production of the vitamins D3 status in the human body. Final report; UV-abhaengige Vitamin D Synthese. Bilanzierung der Expositionszeit durch UV zur Produktion des optimalen Vitamin D{sub 3}-Bedarfes im menschlichen Koerper. Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Knuschke, P.; Lehmann, B.; Pueschel, A.; Roensch, H.

2012-10-15

UV-dependent vitamin D{sub 3} synthesis - balancing of UV exposure time and the production of an optimal vitamin D{sub 3} status in men The adverse health effects on human skin and eyes by UV radiation have been well known for years. They are known to the public, too. Increased exposures by the UV-B fraction of solar radiation cause e.g. sun burn as an acute skin reaction or an increased risk on skin cancer as a chronic effect. Radiation of the same spectral UV-B range is necessary to induce the essential vitamin D metabolism in men. The UV-induced vitamin D synthesis in the skin supplies the body with more than 90 % while our typical nutrition contributes no more than 10 %. These photobiological effects are diametrically opposed. Therefore, up to now there are contradictory recommendations to the public concerning the health effects of solar UV exposure. The aim of this research project was to evaluate the quantitative and qualitative relations of UV exposure and the vitamin D status in men taking into account different conditions in the population. In result, well-balanced recommendations on optimal UV exposures for the different fractions of the population should be elaborated, realizing health protection aspects against detrimental UV effects. A literature survey (updated in 2011) summarizes the current knowledge on the vitamin D metabolism, on the effects of the hormone vitamin D and on the stage of the current discussion on the optimal vitamin D status. In a number of studies of this project the effects of UV exposure on the vitamin D status (25OH-vitamin D{sub 3} und 1,25OH-vitamin D{sub 3}) were investigated. Exposure parameters were the photobiologically effective UV dose (with respect to the minimal erythema dose MED = individual sun burn dose in each investigated volunteer) and the extent of the exposed skin area: face and hands (like everyday conditions) or whole body respectively. Serial UV exposures were applied by natural solar UV radiation or by

Evaluation of thermal control coatings for use on solar dynamic radiators in low earth orbit

Science.gov (United States)

Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

1991-01-01

Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

Environmentally benign silicon solar cell manufacturing

Energy Technology Data Exchange (ETDEWEB)

Tsuo, Y.S. [National Renewable Energy Lab., Golden, CO (United States); Gee, J.M. [Sandia National Labs., Albuquerque, NM (United States); Menna, P. [National Agency for New Technologies Energy and Environment, Portici (Italy); Strebkov, D.S.; Pinov, A.; Zadde, V. [Intersolarcenter, Moscow (Russian Federation)

1998-09-01

The manufacturing of silicon devices--from polysilicon production, crystal growth, ingot slicing, wafer cleaning, device processing, to encapsulation--requires many steps that are energy intensive and use large amounts of water and toxic chemicals. In the past two years, the silicon integrated-circuit (IC) industry has initiated several programs to promote environmentally benign manufacturing, i.e., manufacturing practices that recover, recycle, and reuse materials resources with a minimal consumption of energy. Crystalline-silicon solar photovoltaic (PV) modules, which accounted for 87% of the worldwide module shipments in 1997, are large-area devices with many manufacturing steps similar to those used in the IC industry. Obviously, there are significant opportunities for the PV industry to implement more environmentally benign manufacturing approaches. Such approaches often have the potential for significant cost reduction by reducing energy use and/or the purchase volume of new chemicals and by cutting the amount of used chemicals that must be discarded. This paper will review recent accomplishments of the IC industry initiatives and discuss new processes for environmentally benign silicon solar-cell manufacturing.

75 FR 66078 - Draft Environmental Impact Statement/Staff Assessment for the Solar Reserve LLC Rice Solar Energy...

Science.gov (United States)

2010-10-27

... Assessment for the Solar Reserve LLC Rice Solar Energy Project, Riverside County, CA (DOE/ EIS-0439) and...) Plan Amendment, as a joint environmental analysis document for the proposed Rice Solar Energy Project... two new on-site wells. Rice Solar Energy, LLC (RSE) has applied to Western to interconnect the...

Ozone layer - climate change interactions. Influence on UV levels and UV related effects

NARCIS (Netherlands)

Kelfkens G; Bregman A; de Gruijl FR; van der Leun JC; Piquet A; van Oijen T; Gieskes WWC; van Loveren H; Velders GJM; Martens P; Slaper H; NOP; LPI; LLO

2002-01-01

Ozone in the atmosphere serves as a partially protective filter against the most harmful part of the solar UV-spectrum. Decreases in ozone lead to increases in ambient UV with a wide variety of adverse effects on human health, aquatic and terrestrial ecosystems and food chains. Human health

Sudden Exposure to Solar UV-B Radiation Reduces Net CO2 Uptake and Photosystem I Efficiency in Shade-Acclimated Tropical Tree Seedlings1

Science.gov (United States)

Krause, G. Heinrich; Grube, Esther; Virgo, Aurelio; Winter, Klaus

2003-01-01

Tree seedlings developing in the understory of the tropical forest have to endure short periods of high-light stress when tree-fall gaps are formed, and direct solar radiation, including substantial UV light, reaches the leaves. In experiments simulating the opening of a tree-fall gap, the response of photosynthesis in leaves of shade-acclimated seedlings (Anacardium excelsum, Virola surinamensis, and Calophyllum longifolium) to exposure to direct sunlight (for 20–50 min) was investigated in Panama (9°N). To assess the effects of solar UV-B radiation (280–320 nm), the sunlight was filtered through plastic films that selectively absorbed UV-B or transmitted the complete spectrum. The results document a strong inhibition of CO2 assimilation by sun exposure. Light-limited and light-saturated rates of photosynthetic CO2 uptake by the leaves were affected, which apparently occurred independently of a simultaneous inhibition of potential photosystem (PS) II efficiency. The ambient UV-B light substantially contributed to these effects. The photochemical capacity of PSI, measured as absorbance change at 810 nm in saturating far-red light, was not significantly affected by sun exposure of the seedlings. However, a decrease in the efficiency of P700 photooxidation by far-red light was observed, which was strongly promoted by solar UV-B radiation. The decrease in PSI efficiency may result from enhanced charge recombination in the reaction center, which might represent an incipient inactivation of PSI, but contributes to thermal dissipation of excessive light energy and thereby to photoprotection. PMID:12586898

Variability of pre-vitamin D3 effectiveness of UV appliances for skin tanning.

Science.gov (United States)

Sayre, Robert M; Dowdy, John C; Shepherd, James G

2010-07-01

While there is limited documentation that certain indoor tanning lamps effectively produce vitamin D, the diversity of such devices has not been extensively surveyed. This study compares the spectral effectiveness of a variety of tanning units, and solar spectra, for ultraviolet (UV) photosynthesis of pre-vitamin D3 (preD3) and UV induced erythema. Well-established techniques exist for the calculation of spectral effectiveness for photobiological responses that have defined action spectra. Using spectroradiometric data from sunlamp measurements, and standard solar reference spectra, we computed effective irradiances using the CIE action spectrum for the production of preD3 in human skin and the ISO/CIE human erythema reference action spectrum. We found, as with sunlight at different times or latitude, the preD3 and erythemal effectiveness of sunlamps varied as a function of the UV-B proportion of the spectrum. Ratios of sunlamp preD3 to erythemal effectiveness ranged from approximately 0.5 to nearly 2.0, similar to ratios for sunlight. Optimal risk to benefit conditions for preD3 from solar UV exposure occurs under high solar altitude, low zenith angle, midday midsummer sunlight. Analogous optimal preD3 exposure conditions are provided by low to intermediate pressure sunlamps with greater UV-B spectral overlap with the preD3 action spectrum. Similar to low altitude or high latitude sunlight, high pressure tanning units, filtered for negligible UV-B emissions, have insignificant vitamin D benefit. We conclude that while vitamin D can be made by both UVB exposure from indoor tanning units and by exposure UVB from sunlight, the effect is also comparably variable. Unlike sunlight, indoor tanning offers privacy and environmental conditions for practical full body exposure, lowering the requisite exposure per skin surface area, and device timers limit the potential of overexposure. Guidance for optimal use of tanning sources for vitamin D benefit is needed. Copyright (c

UV dependent vitamin D syntheses. UV exposure time balancing for optimum production of the vitamins D3 status in the human body. Final report

International Nuclear Information System (INIS)

Knuschke, P.; Lehmann, B.; Pueschel, A.; Roensch, H.

2012-01-01

UV-dependent vitamin D 3 synthesis - balancing of UV exposure time and the production of an optimal vitamin D 3 status in men The adverse health effects on human skin and eyes by UV radiation have been well known for years. They are known to the public, too. Increased exposures by the UV-B fraction of solar radiation cause e.g. sun burn as an acute skin reaction or an increased risk on skin cancer as a chronic effect. Radiation of the same spectral UV-B range is necessary to induce the essential vitamin D metabolism in men. The UV-induced vitamin D synthesis in the skin supplies the body with more than 90 % while our typical nutrition contributes no more than 10 %. These photobiological effects are diametrically opposed. Therefore, up to now there are contradictory recommendations to the public concerning the health effects of solar UV exposure. The aim of this research project was to evaluate the quantitative and qualitative relations of UV exposure and the vitamin D status in men taking into account different conditions in the population. In result, well-balanced recommendations on optimal UV exposures for the different fractions of the population should be elaborated, realizing health protection aspects against detrimental UV effects. A literature survey (updated in 2011) summarizes the current knowledge on the vitamin D metabolism, on the effects of the hormone vitamin D and on the stage of the current discussion on the optimal vitamin D status. In a number of studies of this project the effects of UV exposure on the vitamin D status (25OH-vitamin D 3 und 1,25OH-vitamin D 3 ) were investigated. Exposure parameters were the photobiologically effective UV dose (with respect to the minimal erythema dose MED = individual sun burn dose in each investigated volunteer) and the extent of the exposed skin area: face and hands (like everyday conditions) or whole body respectively. Serial UV exposures were applied by natural solar UV radiation or by simulated solar

Air-processed organic tandem solar cells on glass: toward competitive operating lifetimes

DEFF Research Database (Denmark)

Adams, Jens; Spyropoulos, George D.; Salvador, Michael

2015-01-01

efficiencies of more than 10% the rather limited stability of this type of devices raises concerns towards future commercialization. The tandem concept allows for both absorbing a broader range of the solar spectrum and reducing thermalization losses. We designed an organic tandem solar cell with an inverted...... device geometry comprising environmentally stable active and charge-selecting layers. Under continuous white light irradiation, we demonstrate an extrapolated, operating lifetime in excess of one decade. We elucidate that for the current generation of organic tandem cells one critical requirement...... for long operating lifetimes consists of periodic UV light treatment. These results suggest that new material approaches towards UV-resilient active and interfacial layers may enable efficient organic tandem solar cells with lifetimes competitive with traditional inorganic photovoltaics....

Urban UV environment in a sub-tropical megacity – A measurement and modelling study

Directory of Open Access Journals (Sweden)

Ka-Ming Wai

Full Text Available The variations of solar total UV (UVA + UVB exposure rates in a megacity featured with high-rise buildings during summer months were measured and relevant model predictions were evaluated. The maximum pedestrian-level total solar UV exposure rate was less than the un-obstructed exposure rate at any time, attributing to the prevailing reduction in the diffuse solar radiation due to the obstruction effects of distant buildings. Comparing with the measurements, our coupled model well captured the spatial and temporal variations of the reduction of UV exposure rates. By measurements, large reduction in the solar total UV exposure rate down to 12% of un-obstructed exposure rate due to the building obstruction effects was found, agreeing with our previous simulation results and results from an Australian megacity. On the other hand, building reflection from reflective curtain walls could reach 23% of the un-obstructed solar total UV exposure rate at the ground level. This implied improper building design creating additional harmful effects of solar UV radiation on the environment. The coupled model was also applied to predict the urban UV exposure rates during a tropical-cyclone induced aerosol episode. A well-evaluated urban solar UV model is an important tool for sustainable urban design.

Aplicação de radiação UV artificial e solar no tratamento fotocatalítico de efluentes de curtume Application of artificial and solar UV radiation in the photocatalytic treatment of a tannery effluent

Directory of Open Access Journals (Sweden)

Salomão de Andrade Pascoal

2007-10-01

Full Text Available Tannery effluents are very dangerous for the environment since they contain large amounts of dangerous and biorecalcitrant contaminants (organic matter and Cr(VI. This paper reports the efficiency of heterogeneous photocatalysis, based on the application of solar and artificial radiation, furnished by UV lamps, using TiO2 fixed on a flat plate, in the treatment of synthetic effluents. The results of COD and Cr(VI demonstrate that the use of solar radiation is the most efficient way to perform the photocatalytic treatment of these effluents since a minimum removal of 62 and 61% was observed for Cr(VI and organic matter, respectively.

Thermal Effect on a CIGS Thin-Film Solar Cell P2 Layer by Using a UV Laser

Directory of Open Access Journals (Sweden)

Dyi-Cheng Chen

2014-07-01

Full Text Available This study used ANSYS simulation software for analyzing an ultraviolet (UV (355 nm laser processing system. The laser apparatus was used in a stainless steel CIGS solar cell P2 layer for simulation analysis. CIGS films process order according to SiO2 layer, molybdenum electrode, CIGS absorbed layer, CdS buffered layer, i-ZnO penetrate light layer, TCO front electrode, MgF resist reflected materials, andelectrode materials. The simulation and experimental results were compared to obtain a laser-delineated P2 laser with a low melting and vaporization temperature. According to the simulation results, the laser function time was 135 μs, the UV laser was 0.5 W, and the P2 layer thin films were removed. The experimental results indicated that the electrode pattern of the experiment was similar to that of the simulation result, and the laser process did not damage the base plate. The analysis results confirm that the laser apparatus is effective when applied to a stainless steel CIGS solar cell P2 layer.

Spatial and temporal structures of impulsive bursts from solar flares observed in UV and hard X-rays

Science.gov (United States)

Cheng, C.-C.; Tandberg-Hanssen, E.; Bruner, E. C.; Orwig, L.; Frost, K. J.; Kenny, P. J.; Woodgate, B. E.; Shine, R. A.

1981-01-01

New observations are presented of impulsive UV and hard X-rays bursts in two solar flares obtained with instruments on Solar Maximum Mission. The UV bursts were observed in the Si IV and O IV emission lines, whose intensity ratio is density-sensitive. By comparing the spatially resolved Si IV/O IV observations with the corresponding hard X-ray observations, it is possible to study their spatial and temporal relationships. For one flare, the individual component spikes in the multiply peaked hard X-ray burst can be identified with different discrete Si IV/O IV flaring kernels of size 4 arcsec x 4 arcsec or smaller, which brighten up sequentially in time. For the other, many Si IV/O kernels, widely distributed over a large area, show impulsive bursts at the same time, which correlate with the main peak of the impulsive hard X-ray burst. The density of the flaring Si IV/O IV kernels is in the range from 5 x 10 to the 12th-13th/cu cm.

Inhibition of charge recombination for enhanced dye-sensitized solar cells and self-powered UV sensors by surface modification

Energy Technology Data Exchange (ETDEWEB)

Chu, Liang, E-mail: chuliang@njupt.edu.cn [Advanced Energy Technology Center, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046 (China); Wuhan National Laboratory for Optoelectronics (WNLO)-School of Physics, Huazhong University of Science and Technology (HUST), Wuhan 430074 (China); Qin, Zhengfei; Liu, Wei [School of Materials Science and Engineering (SMSE), Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046 (China); Ma, Xin’guo, E-mail: maxg2013@sohu.com [Hubei Collaborative Innovation Center for High-efficiency Utilization of Solar Energy, Hubei University of Technology, Wuhan 430068 (China)

2016-12-15

Graphical abstract: Inhibition of charge recombination was utilized to prolong electrode lifetime in dye-sensitized solar cells (DSSCs) and self-powered UV sensors based on TiO{sub 2}-modified SnO{sub 2} photoelectrodes. The electrochemical impedance spectroscopy and open-circuit voltage decay measurements indicated that the electron lifetime was significantly prolonged in DSSCs after TiO{sub 2} modification. And in self-powered UV sensors, the sensitivity and response time were enhanced. - Highlights: • The surface modification to inhibit charge recombination was utilized in photovoltaic devices. • Inhibition of charge recombination can prolong electrode lifetime in photovoltaic devices. • Enhanced DSSCs and self-powered UV sensors based on SnO{sub 2} photoelectrodes were obtained by TiO{sub 2} modification. - Abstract: The surface modification to inhibit charge recombination was utilized in dye-sensitized solar cells (DSSCs) and self-powered ultraviolet (UV) sensors based on SnO{sub 2} hierarchical microspheres by TiO{sub 2} modification. For DSSCs with SnO{sub 2} photoelectrodes modified by TiO{sub 2}, the power conversion efficiency (PCE) was improved from 1.40% to 4.15% under standard AM 1.5G illumination (100 mW/cm{sup 2}). The electrochemical impedance spectroscopy and open-circuit voltage decay measurements indicated that the charge recombination was effectively inhibited, resulting in long electron lifetime. For UV sensors with SnO{sub 2} photoelectrodes modified by TiO{sub 2} layer, the self-powered property was more obvious, and the sensitivity and response time were enhanced from 91 to 6229 and 0.15 s to 0.055 s, respectively. The surface modification can engineer the interface energy to inhibit charge recombination, which is a desirable approach to improve the performance of photoelectric nanodevice.

Physiological responses and toxin production of Microcystis aeruginosa in short-term exposure to solar UV radiation.

Science.gov (United States)

Hernando, Marcelo; Minaglia, Melina Celeste Crettaz; Malanga, Gabriela; Houghton, Christian; Andrinolo, Darío; Sedan, Daniela; Rosso, Lorena; Giannuzzi, Leda

2018-01-17

The aim of this study was to evaluate the effects of short-term (hours) exposure to solar UV radiation (UVR, 280-400 nm) on the physiology of Microcystis aeruginosa. Three solar radiation treatments were implemented: (i) PAR (PAR, 400-700 nm), (ii) TUVA (PAR + UVAR, 315-700 nm) and (iii) TUVR (PAR + UVAR + UVBR, 280-700 nm). Differential responses of antioxidant enzymes and the reactive oxygen species (ROS) production to UVR were observed. Antioxidant enzymes were more active at high UVR doses. However, different responses were observed depending on the exposure to UVAR or UVBR and the dose level. No effects were observed on the biomass, ROS production or increased activity of superoxide dismutase (SOD) and catalase (CAT) compared to the control when UVR + PAR doses were lower than 9875 kJ m -2 . For intermediate doses, UVR + PAR doses between 9875 and 10 275 kJ m -2 , oxidative stress increased while resistance was imparted through SOD and CAT in the cells exposed to UVAR. Despite the increased antioxidant activity, biomass decrease and photosynthesis inhibition were observed, but no effects were observed with added exposure to UVBR. At the highest doses (UVR + PAR higher than 10 275 kJ m -2 ), the solar UVR caused decreased photosynthesis and biomass with only activation of CAT by UVBR and SOD and CAT by UVAR. In addition, for such doses, a significant decrease of microcystins (MCs, measured as MC-LR equivalents) was observed as a consequence of UVAR. This study facilitates our understanding of the SOD and CAT protection according to UVAR and UVBR doses and cellular damage and reinforces the importance of UVR as an environmental stressor. In addition, our results support the hypothesized antioxidant function of MCs.

Comparison of UV-Curing, Hotmelt, and Pressure Sensitive Adhesive as Roll-to-Roll Encapsulation Methods for Polymer Solar Cells

DEFF Research Database (Denmark)

Hösel, Markus; Søndergaard, Roar R.; Jørgensen, Mikkel

2013-01-01

The most distinct advantage of the polymer solar cell is the possibility for roll-to-roll (R2R) fabrication compatibility based on printing and coating processes. The R2R encapsulation is the last crucial process step in the manufacturing workflow and is evaluated in this study. Polymer solar cell...... modules are directly printed on barrier foil and encapsulated with the same barrier foil either on the backside or on both sides of the device. The three lamination methods comprise of UV-curable epoxy resin, hotmelt, and pressure sensitive adhesive (PSA). It is shown that a single sided encapsulation...... of the PSA method is the fastest method (in this study) it generates a considerable amount of waste (paper liner) and two lamination steps are required to achieve a sufficient lifetime. We conclude that UV-curing presents the largest advantages of all methods with a good upscaling potential and low embodied...

Photolytic degradation of polybromodiphenyl ethers under UV-lamp and solar irradiations

Energy Technology Data Exchange (ETDEWEB)

Shih, Yang-hsin, E-mail: yhs@nchu.edu.tw [Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 402, Taiwan (China); Wang, Chun-Kang [Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 402, Taiwan (China)

2009-06-15

Polybromodiphenyl ethers (PBDEs) are widely used flame retardant additives and have been mainly used in polymers for many plastic and electronic products. PBDEs have been found to bioaccumulate in both aquatic and terrestrial ecosystems and even human bodies. The technical product with the highest use is decabrominated diphenyl ether (BDE-209). Therefore, we chose to examine the solar and UV-lamp degradation of BDE-209. A linear increase of the photodegradation rate constant for BDE-209 was observed with the solar light intensity. The degradation reactions follow the pseudo-first-order kinetics. The photodegradation of BDE-209 produced other less brominated diphenyl ethers under ultraviolet light exposure, suggesting that the photodegradation of BDE-209 is a sequential dehalogenation mechanism. BDE-209 underwent rapid reductive debromination in these photodecomposition experiments. The formation rate constants of three nonabromodiphenyl ethers increase with the order of BDE-206, BDE-207 and BDE-208, indicating debromination mainly occurred at para > meta > ortho positions. These findings of the process properties and reductive debromination mechanism of the photolytic degradation of PBDEs can facilitate the design of remediation processes and also aid in predicting their fate in the environment.

The effectiveness of UV-C radiation for facility-wide environmental disinfection to reduce health care-acquired infections.

Science.gov (United States)

Napolitano, Nathanael A; Mahapatra, Tanmay; Tang, Weiming

2015-12-01

Health care-acquired infections (HAIs) constitute an increasing threat for patients worldwide. Potential contributors of HAIs include environmental surfaces in health care settings, where ultraviolet-C radiation (UV-C) is commonly used for disinfection. This UV-C intervention-based pilot study was conducted in a hospital setting to identify any change in the incidence of HAIs before and after UV-C intervention, and to determine the effectiveness of UV-C in reducing pathogens. In a hospital in Culver City, CA, during 2012-2013, bactericidal doses of UV-C radiation (254 nm) were delivered through a UV-C-based mobile environmental decontamination unit. The UV-C dosing technology and expertise of the specifically trained personnel were provided together as a dedicated service model by a contracted company. The incidence of HAIs before and after the intervention period were determined and compared. The dedicated service model dramatically reduced HAIs (incidence difference, 1.3/1000 patient-days, a 34.2% reduction). Reductions in the total number and incidence proportions (28.8%) of HAIs were observed after increasing and maintaining the coverage of UV-C treatments. The dedicated service model was found to be effective in decreasing the incidence of HAIs, which could reduce disease morbidity and mortality in hospitalized patients. This model provides a continuously monitored and frequently UV-C-treated patient environment. This approach to UV-C disinfection was associated with a decreased incidence of HAIs. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Materials That Enhance Efficiency and Radiation Resistance of Solar Cells

Science.gov (United States)

Sun, Xiadong; Wang, Haorong

2012-01-01

A thin layer (approximately 10 microns) of a novel "transparent" fluorescent material is applied to existing solar cells or modules to effectively block and convert UV light, or other lower solar response waveband of solar radiation, to visible or IR light that can be more efficiently used by solar cells for additional photocurrent. Meanwhile, the layer of fluorescent coating material remains fully "transparent" to the visible and IR waveband of solar radiation, resulting in a net gain of solar cell efficiency. This innovation alters the effective solar spectral power distribution to which an existing cell gets exposed, and matches the maximum photovoltaic (PV) response of existing cells. By shifting a low PV response waveband (e.g., UV) of solar radiation to a high PV response waveband (e.g. Vis-Near IR) with novel fluorescent materials that are transparent to other solar-cell sensitive wavebands, electrical output from solar cells will be enhanced. This approach enhances the efficiency of solar cells by converting UV and high-energy particles in space that would otherwise be wasted to visible/IR light. This innovation is a generic technique that can be readily implemented to significantly increase efficiencies of both space and terrestrial solar cells, without incurring much cost, thus bringing a broad base of economical, social, and environmental benefits. The key to this approach is that the "fluorescent" material must be very efficient, and cannot block or attenuate the "desirable" and unconverted" waveband of solar radiation (e.g. Vis-NIR) from reaching the cells. Some nano-phosphors and novel organometallic complex materials have been identified that enhance the energy efficiency on some state-of-the-art commercial silicon and thin-film-based solar cells by over 6%.

Effects of ozone depletion and UV-B radiation on humans and the environment

Energy Technology Data Exchange (ETDEWEB)

Solomon, K.R. [Guelph Univ., ON (Canada). Centre for Toxicology

2008-03-15

This paper summarized current research related to the effects of ultraviolet (UV-B) radiation on human health and the environment. Effects included direct responses in human as well as effects on biogeochemistry and the environmental cycling of substances. UV radiation has many harmful effects on the skin, eyes, and immune systems of humans. Skin cancer is a leading cause of death among fair-skinned populations exposed to UV radiation. The role of UV radiation in cataract formation was discussed, as well as issues related to the suppression of immune responses. The link between sunlight exposure and vitamin D levels in human populations was examined. The effects of UV radiation on terrestrial and aquatic ecosystems were reviewed. Issues related to biogeochemistry and atmospheric processes were discussed. The review suggested that changes in the intensity of solar UV radiation due to ozone depletion will have important repercussions for all organisms on the planet. It was concluded that the combined effects of UV-B radiation and climate change will not be easy to predict. 201 refs., 4 figs.

Solar UV irradiation-induced production of N2O from plant surfaces - low emissions rates but all over the world.

Science.gov (United States)

Mikkelsen, T. N.; Bruhn, D.; Ambus, P.

2016-12-01

Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2 h-1, mostly due to the UV component. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

An in vitro strategy to evaluate the phototoxicity of solar UV at the molecular and cellular level: application to photoprotection assessment.

Science.gov (United States)

Marrot, L; Belaidi, J P; Chaubo, C; Meunier, J R; Perez, P; Agapakis-Causse, C

1998-09-01

Skin cancers are among the most common human cancers and have an increasing incidence. The ultraviolet radiation components of sunlight play a major role in skin tumor induction and development. Cellular DNA has been identified as a target for most of the biological effects of UV, and the induction of photodamage is considered as the initiating step of photocarcinogenesis. Thus, effective photoprotection of DNA against harmful overex-posure to solar UV is a critical issue. The efficiency of a sunscreen is usually tested with respect to its ability to prevent skin erythema, but conceivably, more data are required at the molecular and cellular level in order to ascertain protection against photocarcinogenic risk. In the present study, we define a strategy based on the use of various in vitro models and solar-simulated light to evaluate photodamage and photoprotection: -Supercoiled circular plasmid DNA for detection of structural alterations. -The yeast Saccharomyces cerevisiae to evaluate cytotoxicity and genotoxicity. -The single-cell gel electrophoresis or comet assay to determine DNA damage and DNA repair in human keratinocytes. -p53 expression as a hallmark for genotoxic stress. -Induction of pigmentation in human melanocytes. In conditions where light source, spectrum and control of radiation delivery were precisely defined, we have demonstrated that the wide spectrum UVA sunscreen Mexoryl SX protects from the cytotoxicity and genotoxicity of solar UV.

Short- and long-term variability of spectral solar UV irradiance at Thessaloniki, Greece: effects of changes in aerosols, total ozone and clouds

Directory of Open Access Journals (Sweden)

I. Fountoulakis

2016-03-01

Full Text Available In this study, we discuss the short- and the long-term variability of spectral UV irradiance at Thessaloniki, Greece, using a long, quality-controlled data set from two Brewer spectrophotometers. Long-term changes in spectral UV irradiance at 307.5, 324 and 350 nm for the period 1994–2014 are presented for different solar zenith angles and discussed in association with changes in total ozone column (TOC, aerosol optical depth (AOD and cloudiness observed in the same period. Positive changes in annual mean anomalies of UV irradiance, ranging from 2 to 6 % per decade, have been detected both for clear- and all-sky conditions. The changes are generally greater for larger solar zenith angles and for shorter wavelengths. For clear-skies, these changes are, in most cases, statistically significant at the 95 % confidence limit. Decreases in the aerosol load and weakening of the attenuation by clouds lead to increases in UV irradiance in the summer, of 7–9 % per decade for 64° solar zenith angle. The increasing TOC in winter counteracts the effect of decreasing AOD for this particular season, leading to small, statistically insignificant, negative long-term changes in irradiance at 307.5 nm. Annual mean UV irradiance levels are increasing from 1994 to 2006 and remain relatively stable thereafter, possibly due to the combined changes in the amount and optical properties of aerosols. However, no statistically significant corresponding turning point has been detected in the long-term changes of AOD. The absence of signatures of changes in AOD in the short-term variability of irradiance in the UV-A may have been caused by changes in the single scattering albedo of aerosols, which may counteract the effects of changes in AOD on irradiance. The anti-correlation between the year-to-year variability of the irradiance at 307.5 nm and TOC is clear and becomes clearer as the AOD decreases.

Characterization of Candidate Solar Sail Material Exposed to Space Environmental Effects

Science.gov (United States)

Edwards, David; Hovater, Mary; Hubbs, Whitney; Wertz, George; Hollerman, William; Gray, Perry

2003-01-01

Solar sailing is a unique form of propulsion where a spacecraft gains momentum from incident photons. Solar sails are not limited by reaction mass and provide continual acceleration, reduced only by the lifetime of the lightweight film in the space environment and the distance to the Sun. Once thought to be difficult or impossible, solar sailing has come out of science fiction and into the realm of possibility. Any spacecraft using this method would need to deploy a thin sail that could be as large as many kilometers in extent. The availability of strong, ultra lightweight, and radiation resistant materials will determine the future of solar sailing. The National Aeronautics and Space Administration's Marshall Space Flight Center (MSFC) is concentrating research into the utilization of ultra lightweight materials for spacecraft propulsion. The Space Environmental Effects Team at MSFC is actively characterizing candidate solar sail material to evaluate the thermo-optical and mechanical properties after exposure to space environmental effects. This paper will describe the exposure of candidate solar sail materials to emulated space environmental effects including energetic electrons, combined electrons and Ultraviolet radiation, and hypervelocity impact of irradiated solar sail material. This paper will describe the testing procedure and the material characterization results of this investigation.

UV-induced carbon monoxide emission from living vegetation

DEFF Research Database (Denmark)

Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

2013-01-01

The global burden of carbon monoxide (CO) is rather uncertain. In this paper we address the potential for UV-induced CO emission by living terrestrial vegetation surfaces. Real-time measurements of CO concentrations were made with a cavity enhanced laser spectrometer connected in closed loop...... to either an ecosystem chamber or a plant-leaf scale chamber. Leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation as well as the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature......, indicating an abiotic process. The emission of CO in response to the UV-component of natural solar radiation was also evident at the ecosystem scale....

Solar energy systems: Sustainable or not? Environmental effects of materials of solar systems with Eco-Quantum: the break even point

International Nuclear Information System (INIS)

Knapen, M.; Anink, D.; Donze, G.

2000-01-01

Solar systems seem a sustainable way of providing energy. But are nowadays PV-systems with materials like heavy metals sustainable? Is PV really environmentally sound with the actual efficiency? And what about solar collectors? This paper provides the answers and indicates improvement options for solar systems to make them more overall sustainable in the future. With Eco-Quantum, a simulation tool for analysing the environmental performance of buildings, the overall environmental profit of buildings with PV-systems and solar collectors is shown. It calculates the environmental effects during the entire life cycle of a complete building ('cradle to grave'). This includes the impact of energy and water use, maintenance during use phase, differences in durability of parts or construction needs, like adhesives and nails. The basis of Eco-Quantum is environmental life cycle assessment (LCA). IEA BCS Annex 31 indicated Eco-Quantum as one of the most sophisticated tools to calculate environment al performance of a build ing. The results of Eco-Quantum are the environmental indicators: Exhaustion of resources; Emissions; Energy and Waste. Options like PV and solar collectors are investigated in a reference building. On the one hand the energy during use is reduced by the options. On the other hand the environmental effects because of materials exhaustion of resources and emissions during production is increased as a consequence of additional material use. (au)

DNA damage caused by UV- and near UV-irradiation

International Nuclear Information System (INIS)

Ohnishi, Takeo

1986-01-01

Much work with mutants deficient in DNA repair has been performed concerning UV-induced DNA damage under the condition where there is no artificial stimulation. In an attempt to infer the effects of solar wavelengths, the outcome of the work is discussed in terms of cellular radiation sensitivity, unscheduled DNA synthesis, and mutation induction, leading to the conclusion that some DNA damage occurs even by irradiation of the shorter wavelength light (270 - 315 nm) and is repaired by excision repair. It has been thought to date that pyrimidine dimer (PD) plays the most important role in UV-induced DNA damage, followed by (6 - 4) photoproducts. As for DNA damage induced by near UV irradiation, the yield of DNA single-strand breaks and of DNA-protein crosslinking, other than PD, is considered. The DNA-protein crosslinking has proved to be induced by irradiation at any wavelength of UV ranging from 260 to 425 nm. Near UV irradiation causes the inhibition of cell proliferation to take place. (Namekawa, K.)

76 FR 80385 - Draft Environmental Impact Statement and Proposed Maricopa Sun Solar Complex Multi-Species...

Science.gov (United States)

2011-12-23

.... Operation related activities could include solar panel maintenance, on-site parking, operation of solar...-FXES11120800000F2-123] Draft Environmental Impact Statement and Proposed Maricopa Sun Solar Complex Multi-Species... National Environmental Policy Act for the proposed Maricopa Sun Solar Complex Habitat Conservation Plan...

Subthreshold UV radiation-induced peroxide formation in cultured corneal epithelial cells: the protective effects of lactoferrin

International Nuclear Information System (INIS)

Shimmura, Shigeto; Suematsu, Makoto; Shimoyama, Masaru; Oguchi, Yoshihisa; Ishimura, Yuzuru

1996-01-01

Acute exposure to suprathreshold ultraviolet B radiation (UV-B) is known to cause photokeratitis resulting from the necrosis and shedding of corneal epithelial cells. However, the corneal effects of low dose UV-B in the environmental range is less clear. In this study, subthreshold UV-B was demonstrated to cause non-necrotic peroxide formation in cultured corneal epithelial cells, which was attenuated by the major tear protein lactoferrin. Intracellular oxidative insults and cell viability of rabbit corneal epithelial cells (RCEC) were assessed by dual-color digital microfluorography using carboxydichlorofluorescin (CDCFH) diacetate bis (acetoxymethyl) ester, a hydroperoxide-sensitive fluoroprobe, and propidium iodode (PI) respectively. The magnitude of UV-induced oxidative insults was calibrated by concentrations of exogenously applied H 2 O 2 which evoke compatible levels of CDCFH oxidation. Exposure of RCEC to low-dose UV-B (2.0 mJ cm -2 at 313 nm, 10.0 mJ cm -2 total UV-B) caused intracellular oxidative changes which were equivalent to those elicited by 240 μM hydrogen peroxide under the conditions of the study. The changes were dose dependent, non-necrotic, and were partially inhibited by lactoferrin ( 1 mg ml -1 ) but not by iron-saturated lactoferrin. Pretreatment with deferoxamine (2 mΜ) or catalase (100 U ml -1 ) also attenuated the UV-induced oxidative stress. The results indicate that UV-B comparable to solar irradiation levels causes significant intracellular peroxide formation in corneal epithelial cells, and that lactoferrin in tears may have a physiological role in protecting the corneal epithelium from solar UV irradiation. (Author)

Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

Science.gov (United States)

Caputo, Fanny; de Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

2015-09-01

Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields.

Photocatalytic treatment of an industrial effluent using artificial and solar UV radiation: an operational cost study on a pilot plant scale.

Science.gov (United States)

Durán, A; Monteagudo, J M; San Martín, I

2012-05-15

The aim of this work was to study the operation costs of treating a real effluent from an integrated gasification combined cycle (IGCC) power station located in Spain. The study compares different homogeneous photocatalytic processes on a pilot plant scale using different types of radiation (artificial UV or solar UV with a compound parabolic collector). The efficiency of the processes was evaluated by an analysis of the total organic carbon (TOC) removed. The following processes were considered in the study: (i) a photo-Fenton process at an artificial UV pilot plant (with the initial addition of H(2)O(2)), (ii) a modified photo-Fenton process with continuous addition of H(2)O(2) and O(2) to the system and (iii) a ferrioxalate-assisted solar photo-Fenton process at a compound parabolic collector (CPC) pilot plant. The efficiency of these processes in degrading pollutants has been studied previously, and the results obtained in each of those studies have been published elsewhere. The operational costs due to the consumption of electrical energy, reagents and catalysts were calculated from the optimal conditions of each process. The results showed that the solar photo-Fenton system was economically feasible, being able to achieve up to 75% mineralization with a total cost of 6 €/m(3), which can be reduced to 3.6 €/m(3) by subtracting the electrical costs because the IGCC plant is self-sufficient in terms of energy. Copyright © 2011 Elsevier Ltd. All rights reserved.

The mechanisms of UV mutagenesis

International Nuclear Information System (INIS)

Ikehata, Hironobu; Ono, Tetsuya

2011-01-01

Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: ''error-free'' bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases-the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation. (author)

Solar Sail Material Performance Property Response to Space Environmental Effects

Science.gov (United States)

Edwards, David L.; Semmel, Charles; Hovater, Mary; Nehls, Mary; Gray, Perry; Hubbs, Whitney; Wertz, George

2004-01-01

The National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) continues research into the utilization of photonic materials for spacecraft propulsion. Spacecraft propulsion, using photonic materials, will be achieved using a solar sail. A solar sail operates on the principle that photons, originating from the sun, impart pressure to the sail and therefore provide a source for spacecraft propulsion. The pressure imparted to a solar sail can be increased, up to a factor of two, if the sun-facing surface is perfectly reflective. Therefore, these solar sails are generally composed of a highly reflective metallic sun-facing layer, a thin polymeric substrate and occasionally a highly emissive back surface. Near term solar sail propelled science missions are targeting the Lagrange point 1 (Ll) as well as locations sunward of L1 as destinations. These near term missions include the Solar Polar Imager and the L1 Diamond. The Environmental Effects Group at NASA s Marshall Space Flight Center (MSFC) continues to actively characterize solar sail material in preparation for these near term solar sail missions. Previous investigations indicated that space environmental effects on sail material thermo-optical properties were minimal and would not significantly affect the propulsion efficiency of the sail. These investigations also indicated that the sail material mechanical stability degrades with increasing radiation exposure. This paper will further quantify the effect of space environmental exposure on the mechanical properties of candidate sail materials. Candidate sail materials for these missions include Aluminum coated Mylar[TM], Teonex[TM], and CPl (Colorless Polyimide). These materials were subjected to uniform radiation doses of electrons and protons in individual exposures sequences. Dose values ranged from 100 Mrads to over 5 Grads. The engineering performance property responses of thermo-optical and mechanical properties were

Wavelength-dependent induction of UV absorbing mycosporine-like amino acids in the red alga Chondrus crispus under natural solar radiation

NARCIS (Netherlands)

Krabs, G; Bischof, K; Hanelt, D; Karsten, U; Wiencke, C

2002-01-01

Polychromatic response spectra for the induction of UV absorbing mycosporine-like amino acids (MAAs) were calculated after exposing small thalli of the red alga Chondrus crispus under various cut-off filters to natural solar radiation on the North Sea island Helgoland, Germany. The laboratory-grown

Solar Cycle 24 UV Radiation: Lowest in more than 6 Decades

Science.gov (United States)

Schroder, Klaus-Peter; Mittag, Marco; Schmitt, J. H. M. M.

2015-01-01

Using spectra taken by the robotic telescope ``TIGRE'' (see Fig. 1 and the TIGRE-poster presented by Schmitt et al. at this conference) and its mid-resolution (R=20,000) HEROS double-channel echelle spectrograph, we present our measurements of the solar Ca II H&K chromospheric emission. Using moonlight, we applied the calibration and definition of the Mt. Wilson S-index , which allows a direct comparison with historic observations, reaching back to the early 1960's. At the same time, coming from the same EUV emitting plage regions, the Ca II H&K emission is a good proxy for the latter, which is of interest as a forcing factor in climate models. Our measurements probe the weak, asynchronous activity cycle 24 around its 2nd maximum during the past winter. Our S-values suggest that this maximum is the lowest in chromospheric emission since at least 60 years -- following the longest and deepest minimum since a century. Our observations suggest a similarly long-term (on a scale of decades) low of the far-UV radiation, which should be considered by the next generation of climate models. The current, very interesting activity behaviour calls for a concerted effort on long-term solar monitoring.

Improved UV-B screening capacity does not prevent negative effects of ambient UV irradiance on PSII performance in High Arctic plants. Results from a six year UV exclusion study

DEFF Research Database (Denmark)

Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

2010-01-01

Long-term responses of ambient solar ultraviolet (UV) radiation were investigated on Salix arctica and Vaccinium uliginosum in a High Arctic heath ecosystem in Zackenberg, northeast Greenland. Over a period of six years, UV exclusion was conducted in the growing season by means of filters: 60% UV......, exposing the vegetation to high spring UV-B, and to be present in the future to the degree the ozone layer is not fully recovered....

Quality assurance of the UV irradiances of the UV-B Monitoring and Research Program: the Mauna Loa test case

Science.gov (United States)

Zempila, Melina Maria; Davis, John; Janson, George; Olson, Becky; Chen, Maosi; Durham, Bill; Simpson, Scott; Straube, Jonathan; Sun, Zhibin; Gao, Wei

2017-09-01

The USDA UV-B Monitoring and Research Program (UVMRP) is an ongoing effort aiming to establish a valuable, longstanding database of ground-based ultraviolet (UV) solar radiation measurements over the US. Furthermore, the program aims to achieve a better understanding of UV variations through time, and develop a UV climatology for the Northern American section. By providing high quality radiometric measurements of UV solar radiation, UVMRP is also focusing on advancing science for agricultural, forest, and range systems in order to mitigate climate impacts. Within these foci, the goal of the present study is to investigate, analyze, and validate the accuracy of the measurements of the UV multi-filter rotating shadowband radiometer (UV-MFRSR) and Yankee (YES) UVB-1 sensor at the high altitude, pristine site at Mauna Loa, Hawaii. The response-weighted irradiances at 7 UV channels of the UV-MFRSR along with the erythemal dose rates from the UVB-1 radiometer are discussed, and evaluated for the period 2006-2015. Uncertainties during the calibration procedures are also analyzed, while collocated groundbased measurements from a Brewer spectrophotometer along with model simulations are used as a baseline for the validation of the data. Besides this quantitative research, the limitations and merits of the existing UVMRP methods are considered and further improvements are introduced.

The effect of solarradiation and UV photons on the CR-39 nuclear track detector

International Nuclear Information System (INIS)

Saad, A.F.

2003-01-01

The effects induced in the CR-39 polymer detector by total solar radiation (TSR) and UV photons were investigated. Thr exposure of detector samples to solar photons was carried out according to certain conditions. The TSR exposure period started in the middle of july and lasted unitel 12 th of september. 2000: the hottest months in zagazig, egypt. Another set of detector samples was exposed to UV photons from a UV lamp for different intervals. After UV exposure, these detectors were analysed with an FT-IR sepectrometer of jasco type 5300 in transmission mode. The FT-IR spectra does not show any considerable modifications due to UV irradiation in that detector. The effects of UV light were compared with those of solar radiation containing ultraviolet photons , on the registration properties of this polymer detector. Preliminaryresults revealed a proportionate increase in bluk etch rate of CR-39 detector with the increase of exposure time to the solar radiation. The results indicated that the CR-39 polymer detector can be used as a solar radiation dosimeter

Photocatalytic degradation of cylindrospermopsin under UV-A, solar and visible light using TiO2. Mineralization and intermediate products.

Science.gov (United States)

Fotiou, Theodora; Triantis, Theodoros; Kaloudis, Triantafyllos; Hiskia, Anastasia

2015-01-01

Cyanobacteria (blue-green algae) are considered an important water quality problem, since several genera can produce toxins, called cyanotoxins that are harmful to human health. Cylindrospermopsin (CYN) is an alkaloid-like potent cyanotoxin that has been reported in water reservoirs and lakes worldwide. In this paper the removal of CYN from water by UV-A, solar and visible light photocatalysis was investigated. Two different commercially available TiO2 photocatalysts were used, i.e., Degussa P25 and Kronos-vlp7000. Complete degradation of CYN was achieved with both photocatalysts in 15 and 40 min under UV-A and 40 and 120 min under solar light irradiation, for Degussa P25 and Kronos vlp-7000 respectively. Experiments in the absence of photocatalysts showed that direct photolysis was negligible. Under visible light irradiation only the Kronos vlp-7000 which is a visible light activated catalyst was able to degrade CYN. A number of intermediates were identified and a complete degradation pathway is proposed, leading to the conclusion that hydroxyl radical attack is the main mechanism followed. TOC and inorganic ions (NO2-, NO3-, SO4(2-) and NH4+) determinations suggested that complete mineralization of CYN was achieved under UV-A in the presence of Degussa P25. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adaption of an array spectroradiometer for total ozone column retrieval using direct solar irradiance measurements in the UV spectral range

Science.gov (United States)

Zuber, Ralf; Sperfeld, Peter; Riechelmann, Stefan; Nevas, Saulius; Sildoja, Meelis; Seckmeyer, Gunther

2018-04-01

A compact array spectroradiometer that enables precise and robust measurements of solar UV spectral direct irradiance is presented. We show that this instrument can retrieve total ozone column (TOC) accurately. The internal stray light, which is often the limiting factor for measurements in the UV spectral range and increases the uncertainty for TOC analysis, is physically reduced so that no other stray-light reduction methods, such as mathematical corrections, are necessary. The instrument has been extensively characterised at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. During an international total ozone measurement intercomparison at the Izaña Atmospheric Observatory in Tenerife, the high-quality applicability of the instrument was verified with measurements of the direct solar irradiance and subsequent TOC evaluations based on the spectral data measured between 12 and 30 September 2016. The results showed deviations of the TOC of less than 1.5 % from most other instruments in most situations and not exceeding 3 % from established TOC measurement systems such as Dobson or Brewer.

Effects of UV radiation on freshwater metazooplankton

International Nuclear Information System (INIS)

Tartarotti, B.

1999-06-01

There is evidence that fluxes of solar ultraviolet-B radiation (UV-B, 290-320 nm) are increasing over wide parts of the earth's surface due to stratospheric ozone depletion. UV radiation (290-400 nm) can have damaging effects on biomolecules and cell components that are common to most living organisms. The aim of this thesis is to gain a more thorough understanding of the potential impacts of solar radiation on freshwater metazooplankton. To detect UV-vulnerability in zooplankton populations dominating the zooplankton community of two clear-water, high mountain lakes located one in the Austrian Alps and another in the Chilean Andes, the survival of two copepod species was studied. The organisms were exposed to a 10- to 100-fold increase in UV-B radiation compared to those levels found at their natural, maximum daytime distribution. Both species vertically migrate and are pigmented. UV-absorbing compounds with a maximum absorption at ∼334 nm were also detected. Cyclops abyssorum tatricus, a common cyclopoid copepod species of Alpine lakes, was highly resistant to UV-B radiation and no significant lethal effect was observed. The calanoid copepod Boeckella gracilipes, frequent in Andean lakes, had a mortality ∼5 times higher in the treatment receiving full sunlight than in the UV-B excluded treatment (3.2 %) only when exposed for 70 h. The resistance of B. gracilipes was higher than that reported in the literature for the same species suggesting the existence of intraspecific differences in UV sensitivity. Survival, fecundity and development of the zooplankton community of a clear-water, high elevation Andean lake (33 o S) were studied with mesocosms experiments after prolonged UV exposure (48 days). When exposed to full sunlight, the population of the cladoceran Chydorus sphaericus and the rotifer Lepadella ovalis were strongly inhibited by UV-B, whereas both species were resistant to UV-A radiation. Conversely, UV-B radiation had no effect on the survival of the

Environmental effects of ozone depletion, UV radiation and interactions with climate change: UNEP Environmental Effects Assessment Panel, update 2017

Science.gov (United States)

The Environmental Effects Assessment Panel (EEAP) is one of three Panels of experts that inform the Parties to the Montreal Protocol. The EEAP focuses on the effects of UV radiation on human health, terrestrial and aquatic ecosystems, air quality, and materials, as well as on the...

Role of solar ultraviolet radiation in 'natural' water purification

Energy Technology Data Exchange (ETDEWEB)

Calkins, J; Buckles, J D; Moeller, J R [Kentucky Univ., Lexington (USA)

1976-07-01

The concentration of Eschericia coli in the input and output of a tertiary wastewater system (4 lagoons) has been monitored over an 11 month period. The integrated flux of biologically active solar ultraviolet (UV) radiation was measured during this period. By also determining (1) the effective temperature in the system, (2) the growth rate of E.coli at the effective temperature, (3) the penetration of the solar UV into the lagoons, (4) the dose-response relation for killing of E.coli by UV and (5) the retention time of water in the system, it is possible to compare the 'die off' expected from solar UV exposure to the actual 'die off' observed for different batches of water. The observed killing of E.coli was quite close to the values calculated, considering the numerous factors involved. Solar UV light would thus seem to be a very important factor in the natural purification of water. Because each successful species must possess characteristics (physiological or behavioral) which provide adequate resistance to solar UV, the ecological role of solar UV radiation has not been widely appreciated.

Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

KAUST Repository

Caputo, Fanny

2015-08-20

Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields. © The Royal Society of Chemistry 2015.

Online educative activities for solar ultraviolet radiation based on measurements of cloud amount and solar exposures.

Science.gov (United States)

Parisi, A V; Downs, N; Turner, J; Amar, A

2016-09-01

A set of online activities for children and the community that are based on an integrated real-time solar UV and cloud measurement system are described. These activities use the functionality of the internet to provide an educative tool for school children and the public on the influence of cloud and the angle of the sun above the horizon on the global erythemal UV or sunburning UV, the diffuse erythemal UV, the global UVA (320-400nm) and the vitamin D effective UV. Additionally, the units of UV exposure and UV irradiance are investigated, along with the meaning and calculation of the UV index (UVI). This research will help ensure that children and the general public are better informed about sun safety by improving their personal understanding of the daily and the atmospheric factors that influence solar UV radiation and the solar UV exposures of the various wavebands in the natural environment. The activities may correct common misconceptions of children and the public about UV irradiances and exposure, utilising the widespread reach of the internet to increase the public's awareness of the factors influencing UV irradiances and exposures in order to provide clear information for minimizing UV exposure, while maintaining healthy, outdoor lifestyles. Copyright © 2016 Elsevier B.V. All rights reserved.

Environmental assessment of different solar driven advanced oxidation processes

Energy Technology Data Exchange (ETDEWEB)

Munoz, Ivan; Rieradevall, Joan [Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Torrades, Francesc [Departament d' Enginyeria Quimica, ETSEI de Terrassa, Universitat Politecnica de Catalunya, 08222 Terrassa (Barcelona) (Spain); Peral, Jose; Domenech, Xavier [Departament de Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain)

2005-10-01

In this work a comparative environmental assessment of different advanced oxidation processes (AOP's) is performed. Two energy scenarios have been considered according to the energy source used: solar energy and electricity (UVA lamp). A life cycle assessment (LCA) is carried out in order to quantify the environmental impacts of the AOP's. The treatments considered are heterogenous photocatalysis, photo-Fenton reactions, the coupling of heterogeneous photocatalysis and photo-Fenton, and heterogeneous photocatalysis in combination with hydrogen peroxide. These AOP's are applied to the treatment of kraft mill bleaching wastewaters. The system under study includes the production of the catalysts, reagents as well as the production of electricity; eight environmental impact categories are assessed for each AOP: global warming, ozone depletion, aquatic eutrophication, acidification, human toxicity, freshwater aquatic toxicity, photochemical ozone formation, and abiotic resource depletion. the results of the LCA show that the environmental impact of AOP's is caused mainly by the amount of electricity consumed, whereas the impact of producing the reagents and catalysts is comparatively low. For this reason, the solar energy scenario reduces the impact more than 90% for almost all AOP's and impact categories. None of the solar driven AOP's can be identified as the best in all impact categories, but heterogenous photocatalysis and photo-Fenton reactions obtain better results than the remaining treatments, since these treatments do not consume simultaneously both TiO{sub 2} and H{sub 2}O{sub 2}, the chemicals with highest environmental burdens in the system. (author)

The effect of solar UV radiation of four plant species occurring in a coastal grassland vegetation in The Netherlands

Energy Technology Data Exchange (ETDEWEB)

Tosserams, M.; Rozema, J. [Vrije Univ., Dept. of Ecology and Ecotoxicology, Amsterdam (Netherlands); Pais, A. de Sa [Univ. de Tras-os-Montes e Alto Douro, Vila Real (Portugal)

1996-09-01

During the summer of 1992, growth and some physiological parameters of four native plant species occurring in a coastal grassland in The Netherlands, were studied after reduction of solar UV irradiance using different cut-off filters. Biomass production, morphology and photosynthesis of all species tested were unaffected by the different treatments. Litter production of Plantago lanceolata was increased in the absence of the total UV waveband, indicating a possible role for this waveband in plant senescence. Depletion of the total UV waveband from sunlight resulted in alterations in biomass allocation in Calamagrostis epigeios and Urtica dioica while no changes were observed in P. lanceolatata and Verbascum thapsus. In C. epigeios and increase in the specific leaf area was observed, whereas in U. dioica root weight per total plant weight was decreased resulting in an increase in the shoot/root ratio. Both photosynthetic and UV-absorbing pigment concentrations were altered by the different filter applications. When compared to control plants receiving full sunlight, depletion of UV-B resulted in a significant increase in chlorophyll concentration in U. dioica leaves, this however did not affect photosynthetic rate. The presence of UV-B radiation enhanced the UV-absorbance of leaf extract of all species except P. lanceolata. Optical characteristics of the leaves were also changed. Both the quantity (P. lanceolata and U. dioica) and the quality (all species) of radiation transmitted by the leaves was affected by the different treatments. (au) 44 refs.

Fabrication of modified hydrogenated castor oil/GPTMS-ZnO composites and effect on UV resistance of leather.

Science.gov (United States)

Ma, Jianzhong; Duan, Limin; Lu, Juan; Lyu, Bin; Gao, Dangge; Wu, Xionghu

2017-06-16

Leather products are made from the natural skin collagen fibers. It is vulnerable to the environmental factor such as solar ultraviolet irradiation in the using process. Therefore anti-UV performance is a very important quality, particularly for chrome-free leather. ZnO is a well-known UV absorber commonly used in the cosmetic industry. We have investigated its potential to increase the anti-UV performance of chrome-free leather. Modified hydrogenated castor oil/GPTMS-ZnO (MHCO/ GPTMS-ZnO) composites were prepared using spherical ZnO nanoparticles, hydrogenated castor oil, maleic anhydride and sodium bisulfite. MHCO/GPTMS-ZnO composites have better anti-UV ability and stability. MHCO/GPTMS-ZnO composites were applied to the leather processing. The treated samples were exposed to artificial sunlight. Anti-yellowing tests showed that MHCO/GPTMS-ZnO composites significantly improved anti-UV performance of leather.

Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.

Science.gov (United States)

Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource requirements.…

Environmental/Climatic Effect on Stand-Alone Solar Energy Supply ...

African Journals Online (AJOL)

This paper investigates the climatic eects and environmental variations on the performance of a stand-alone photovoltaic system. The eects of partial shading with dierent climate conditions and load resistance variations were examined. A survey of some of the work done in this eld of environmental eect on solar panel was ...

Use of satellite erythemal UV products in analysing the global UV changes

Directory of Open Access Journals (Sweden)

I. Ialongo

2011-09-01

Full Text Available Long term changes in solar UV radiation affect global bio-geochemistry and climate. The satellite-based dataset of TOMS (Total Ozone Monitoring System and OMI (Ozone Monitoring Instrument of erythemal UV product was applied for the first time to estimate the long-term ultraviolet (UV changes at the global scale. The analysis of the uncertainty related to the different input information is presented. OMI and GOME-2 (Global Ozone Monitoring Experiment-2 products were compared in order to analyse the differences in the global UV distribution and their effect on the linear trend estimation.

The results showed that the differences in the inputs (mainly surface albedo and aerosol information used in the retrieval, affect significantly the UV change calculation, pointing out the importance of using a consistent dataset when calculating long term UV changes. The areas where these differences played a major role were identified using global maps of monthly UV changes. Despite the uncertainties, significant positive UV changes (ranging from 0 to about 5 %/decade were observed, with higher values in the Southern Hemisphere at mid-latitudes during spring-summer, where the largest ozone decrease was observed.

The role of solar ultraviolet radiation in 'natural' water purification

International Nuclear Information System (INIS)

Calkins, J.; Buckles, J.D.; Moeller, J.R.

1976-01-01

The concentration of Eschericia coli in the input and output of a tertiary wastewater system (4 lagoons) has been monitored over an 11 month period. The integrated flux of biologically active solar ultraviolet (UV) radiation was measured during this period. By also determining (1) the effective temperature in the system, (2) the growth rate of E.coli at the effective temperature, (3) the penetration of the solar UV into the lagoons, (4) the dose-response relation for killing of E.coli by UV and (5) the retention time of water in the system, it is possible to compare the 'die off' expected from solar UV exposure to the actual 'die off' observed for different batches of water. The observed killing of E.coli was quite close to the values calculated, considering the numerous factors involved. Solar UV light would thus seem to be a very important factor in the natural purification of water. Because each successful species must possess characteristics (physiological or behavioral) which provide adequate resistance to solar UV, the ecological role of solar UV radiation has not been widely appreciated. (author)

77 FR 44267 - Notice of Availability of the Final Programmatic Environmental Impact Statement for Solar Energy...

Science.gov (United States)

2012-07-27

...] Notice of Availability of the Final Programmatic Environmental Impact Statement for Solar Energy... Environmental Impact Statement for Solar Energy Development in Six Southwestern States (Final Programmatic EIS... RMP Amendments, references, and additional information regarding solar energy development are...

Built-in potential shift and Schottky-barrier narrowing in organic solar cells with UV-sensitive electron transport layers.

Science.gov (United States)

Li, Cheng; Credgington, Dan; Ko, Doo-Hyun; Rong, Zhuxia; Wang, Jianpu; Greenham, Neil C

2014-06-28

The performance of organic solar cells incorporating solution-processed titanium suboxide (TiOx) as electron-collecting layers can be improved by UV illumination. We study the mechanism of this improvement using electrical measurements and electroabsorption spectroscopy. We propose a model in which UV illumination modifies the effective work function of the oxide layer through a significant increase in its free electron density. This leads to a dramatic improvement in device power conversion efficiency through several mechanisms - increasing the built-in potential by 0.3 V, increasing the conductivity of the TiOx layer and narrowing the interfacial Schottky barrier between the suboxide and the underlying transparent electrode. This work highlights the importance of considering Fermi-level equilibration when designing multi-layer transparent electrodes.

The possibility of using plastic detectors CR-39 as UV dosimeters

International Nuclear Information System (INIS)

Shweikani, R.; Raja, G.; Sawaf, A.A.

2004-01-01

The effects of solar ultraviolet (SUV) and ultraviolet type A (UVA) produced by a solar UV simulator on CR-39 detectors were studied. This was done using three techniques: 1 - Alpha tracks diameters and tracks densities, 2 - UV-Vis spectrometry and 3 - FTIR spectrometry. The detectors were divided into two groups, the first was exposed to UV and then to alpha particles, the second group was exposed to alpha particles first and then to UV. The results showed that the effect of UVA on CR-39 was not clear using the three techniques. While, the effect of SUV was clear when using UV-Vis and FTIR spectrometric, and not clear when using track parameters. (author)

The possibility of using plastic detectors CR-39 as UV dosimeters

International Nuclear Information System (INIS)

Shweikani, R.; Raja, G.; Sawaf, A.A.

2002-01-01

The effects of solar ultraviolet (SUV) and ultraviolet type A (UVA) produced by a solar UV simulator on CR-39 detectors were studied. This was done using three techniques: 1 - Alpha tracks diameters and tracks densities, 2 - UV-Vis spectrometry and 3 - FTIR spectrometry. The detectors were divided into two groups, the first was exposed to UV and then to alpha particles, the second group was exposed to alpha particles first and then to UV. The results showed that the effect of UVA on CR-39 was not clear using the three techniques. While, the effect of SUV was clear when using UV-Vis and FTIR spectrometric, and not clear when using track parameters

Oxidative stress and enzymatic scavenging of superoxide radicals induced by solar UV-B radiation in Ulva canopies from southern Spain

Directory of Open Access Journals (Sweden)

Kai Bischof

2003-09-01

Full Text Available The generation of reactive oxygen species (ROS and scavenging of the superoxide radical by superoxide dismutase (SOD was studied in mat-like canopies of the green macroalga Ulva rotundata Bliding in a tidal brine pond system in southern Spain. Artificial canopies were covered with different cut-off filters, generating different radiation conditions. ROS and SOD were assessed after three days of exposure. ROS induced lipid peroxidation depended on the position of individual thalli within the canopy and on radiation conditions. Samples exposed to the full solar spectrum were most affected, whereas samples either exposed to photosynthetically active radiation (PAR alone or UV radiation without PAR exhibited fewer peroxidation products. The activity of SOD appeared to be controlled by the impinging UV-A and UV-B radiation and also increased in response to oxidative stress. The results provide evidence for additive effects of high PAR and UV-B under field conditions and support the previously proposed hypothesis that UV-B effects are mediated by an inhibition of the xanthophyll cycle, which increases ROS production and, consequently, causes oxidative damage to components of the photosynthetic machinery, such as proteins and pigments.

Absorption of uv-radiation by Chibro trademark -Uvelin eye drops

International Nuclear Information System (INIS)

Schreder, J.G.; Blumthaler, M.; Daxer, A.; Ettl, A.

1998-01-01

The preparation Chibro trademark -Uvelin is recommended against both solar and artificial uv-radiation. At wavelengths greater than 290 nm and at an effective layer thickness of 10 μm measurements with a high resolution doublemonochromator showed a transmission larger than 90%. The solar spectrum is characterised by almost no irradiance on the earth's surface for wavelengths smaller than 290 nm due to absorption in the atmospheric ozon layer. Therefore, no significant protective effect of the eye-drops against keratitis and cataract under solar exposure can be expected. A significantly better sagging of the radiation of artificial UV-sources with a high amount of UV-C is reached. The recommended application as chemical protective goggles in this spectral range is not permissible. (orig.) [de

75 FR 78980 - Notice of Availability of the Draft Programmatic Environmental Impact Statement for Solar Energy...

Science.gov (United States)

2010-12-17

...] Notice of Availability of the Draft Programmatic Environmental Impact Statement for Solar Energy... Draft Programmatic Environmental Impact Statement (EIS) for Solar Energy Development in Six Southwestern... preferred method of commenting. Mail: Addressed to: Solar Energy Draft Programmatic EIS, Argonne National...

Topical Administration of Manuka Oil Prevents UV-B Irradiation-Induced Cutaneous Photoaging in Mice

Directory of Open Access Journals (Sweden)

Oh Sook Kwon

2013-01-01

Full Text Available Manuka tree is indigenous to New Zealand, and its essential oil has been used as a traditional medicine to treat wounds, fever, and pain. Although there is a growing interest in the use of manuka oil for antiaging skin care products, little is known about its bioactivity. Solar ultraviolet (UV radiation is the primary environmental factor causing skin damage and consequently premature aging. Therefore, we evaluated manuka oil for its effects against photoaging in UV-B-irradiated hairless mice. Topical application of manuka oil suppressed the UV-B-induced increase in skin thickness and wrinkle grading in a dose-dependent manner. Application of 10% manuka oil reduced the average length, depth, and % area of wrinkles significantly, and this was correlated with inhibition of loss of collagen fiber content and epidermal hyperplasia. Furthermore, we observed that manuka oil could suppress UV-B-induced skin inflammation by inhibiting the production of inflammatory cytokines. Taken together, this study provides evidence that manuka oil indeed possesses antiphotoaging activity, and this is associated with its inhibitory activity against skin inflammation induced by UV irradiation.

Environmental aspects of electricity generation from a nanocrystalline dye sensitized solar cell system

International Nuclear Information System (INIS)

Greijer, Helena; Karlson, Lennart; Lindquist, Sten-Eric; Hagfeldt, Anders

2001-01-01

A Life Cycle Assessment, LCA, of a nanocrystalline dye sensitised solar cell (ncDSC) system has been performed, according to the ISO14040 standard. In brief, LCA is a tool to analyse the total environment impact of a product or system from cradle to grave. Six different weighing methods were used to rank and select the significant environmental aspects to study further. The most significant environmental aspects according to the weighing methods are emission of sulphur dioxide and carbon dioxide. Carbon dioxide emission was selected as the environmental indicator depending on the growing attention on the global warming effect. In an environmental comparison of electricity generation from a ncDSC system and a natural gas/combined cycle power plant, the gas power plant would result in 450 g CO 2 /kWh and the ncDSC system in between 19-47 g CO 2 /wWh. The latter can be compared with 42 g CO 2 /kWh, according to van Brummelen et al. 'Life Cycle Assessment of Roof Integrated Solar Cell Systems, (Report: Department of Science, Technology and Society, Utrecht University, The Netherlands, 1994)' for another thin film solar cell system made of amorphous silicon. The most significant activity/component contributing to environmental impact over the life cycle of the ncDSC system is the process energy for producing the solar cell module. Secondly comes the components; glass substrate, frame and junction box. The main improvement from an environmental point of view of the current technology would be an increase in the conversion efficiency from solar radiation to electricity generation and still use low energy demanding production technologies. Also the amount of material in the solar cell system should be minimised and designed to maximise recycling. (Author)

Evaluation of an economical sunlamp that emits a near solar UV power spectrum for conducting photoimmunological and sunscreen immune protection studies

International Nuclear Information System (INIS)

Beasley, D.G.; Roberts, L.K.; Beard, J.; Stanfield, J.W.

1996-01-01

Unlike FS-type UVB sunlamps, which have a significant amount of effective immunosuppressive non-solar UV energy at wavelengths below 295 nm, the immunosuppression effectiveness spectrum of UVA-340 sunlamps was nearly identical to that of a solar simulator. The purpose of this study was to evaluate this sunlamp for conducting photoimmunological and sunscreen immune protection studies. Groups of C3H mice were exposed to a range of UVA-340 sunlamp doses (0.25 kJ/m 2 to 20.0 kJ/m 2 ) to establish a dose-response curve and determine the minimum immune suppression dose (MISD) for induction of local-type suppression of contact hypersensitivity (CH). The MISD, defined as the lowest UV dose given to produce ∼ 50% suppression of the CH response in mice, was determined to be 1.0 kJ/m 2 for UVA-340 sunlamps. Immune protection tests on four marketed sunscreen lotions (sun protection factors [SPF] 4, 8, 15 and 30) were then conducted with UVA-340 sunlamps using MISD as the endpoint. The immune protection factors for these sunscreens were equivalent to the level of protection predicted by their labeled SPF. These results are similar to those we have previously obtained using a solar simulator. (author)

UV Deprivation Influences Social UV Preference in Juvenile Sticklebacks

Directory of Open Access Journals (Sweden)

Ricarda Modarressie

2015-05-01

Full Text Available Social aggregations occur in many different animal taxa and mainly result from non-random assortment. Investigating factors that shape and maintain the composition of social aggregations are among others a main topic for understanding ecological speciation processes. Aggregation decisions are mediated by olfactory and visual cues, which in many animals are extended into the UV part of the electromagnetic spectrum. Here, we were interested in developmental plasticity of social preferences with respect to UV radiation in aquatic organisms. Specifically, we tested whether different lighting environments with respect to UV wavelengths during early life stages influence the shoaling preference in juvenile threespine sticklebacks (Gasterosteus aculeatus. Family (full-sibling groups were split and reared under UV-lacking (UV- and UV-present (UV+ lighting conditions. Subsequent shoal choice experiments, in which test fish from both rearing conditions could simultaneously choose between a shoal seen behind a UV-blocking (UV- and a shoal seen behind a UV-transmitting (UV+ filter, revealed a significant effect of lighting condition during rearing on association preference. Test fish that had been deprived of UV spent significantly more time near the UV- shoal compared to the test fish reared under full-spectrum lighting conditions. The results are discussed with respect to plasticity of the visual system and environmental lighting conditions.

Solar Ethics: A New Paradigm for Environmental Ethics and Education?

Science.gov (United States)

Peters, Michael A.; Hung, Ruyu

2009-01-01

This article provides grounds for a new paradigm of environmental ethics and education based on the centrality of the sun and solar system--a shift from anthropocentrism to solar systemism. The article provides some grounds for this shift from the physical sciences that considers the planet Earth as part of a wider system that is dependent upon…

Optical and thermal design of 1.5-m aperture solar UV visible and IR observing telescope for Solar-C mission

Science.gov (United States)

Suematsu, Y.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.; Horiuchi, T.; Matsumoto, Y.; Takeyama, N.

2017-11-01

order of magnitude more photons than SOT, relatively shorter telescope length of 2.8 m to accommodate a launcher's nosecone size for possible dual-satellite-launch configuration, and much wider observing wavelength from UV (down to 250 nm) through near IR (up to 1100 nm). The large aperture is essentially important to attain scientific goals of the plan-B, especially for accurate diagnostics of the dynamic solar chromosphere as revealed by Hinode, although this make it difficult to design the telescope because of ten times more solar heat load introduced into the telescope. The SUVIT consists of two optically separable components; the telescope assembly (TA) and an accompanying focal plane package equipped with filtergraphs and spectrographs. Opto-mechanical and -thermal performance of the TA is crucial to attain high-quality solar observations and here we present a status of feasible study in its optical and thermal designing for diffraction-limited performance at visible wavelength in a reasonably wide field of view.

Improving radiation data quality of USDA UV-B monitoring and research program and evaluating UV decomposition in DayCent and its ecological impacts

Science.gov (United States)

Chen, Maosi

Solar radiation impacts many aspects of the Earth's atmosphere and biosphere. The total solar radiation impacts the atmospheric temperature profile and the Earth's surface radiative energy budget. The solar visible (VIS) radiation is the energy source of photosynthesis. The solar ultraviolet (UV) radiation impacts plant's physiology, microbial activities, and human and animal health. Recent studies found that solar UV significantly shifts the mass loss and nitrogen patterns of plant litter decomposition in semi-arid and arid ecosystems. The potential mechanisms include the production of labile materials from direct and indirect photolysis of complex organic matters, the facilitation of microbial decomposition with more labile materials, and the UV inhibition of microbes' population. However, the mechanisms behind UV decomposition and its ecological impacts are still uncertain. Accurate and reliable ground solar radiation measurements help us better retrieve the atmosphere composition, validate satellite radiation products, and simulate ecosystem processes. Incorporating the UV decomposition into the DayCent biogeochemical model helps to better understand long-term ecological impacts. Improving the accuracy of UV irradiance data is the goal of the first part of this research and examining the importance of UV radiation in the biogeochemical model DayCent is the goal of the second part of the work. Thus, although the dissertation is separated into two parts, accurate UV irradiance measurement links them in what follows. In part one of this work the accuracy and reliability of the current operational calibration method for the (UV-) Multi-Filter Rotating Shadowband Radiometer (MFRSR), which is used by the U.S. Department of Agriculture UV-B Monitoring and Research Program (UVMRP), is improved. The UVMRP has monitored solar radiation in the 14 narrowband UV and VIS spectral channels at 37 sites across U.S. since 1992. The improvements in the quality of the data result

Rapid maize leaf and immature ear responses to UV-B radiation

International Nuclear Information System (INIS)

Casati, P.; Morrow, D.; Fernandes, J.; Walbot, V.

2011-01-01

Plants have evolved adaptations to environmental factors, including solar radiation. In addition to acting as a developmental and physiological signal, UV-B photons also cause cellular damage. Elevated UV-B radiation has pleiotropic effects on plant development, morphology, and physiology, but the regulation of systemic responses is not well-understood. To gain a better understanding of the initial events in UV-B acclimation, we have analyzed a 10min to 1h time course of transcriptome responses in irradiated and shielded leaves, and immature maize ears to unravel the systemic physiological and developmental responses in exposed and shielded organs. To identify metabolites as possible signaling molecules, we looked for compounds that increased within 5-90 min in both irradiated and shielded leaves, to explain the kinetics of profound transcript changes within 1h. We found that myoinositol is one such candidate metabolite, and it also has support from RNA profiling: after 1h UV-B, transcripts for myoinositol-1-phosphate synthase, are decreased in both irradiated and shielded leaves suggesting down-regulation of biogenesis. We also demonstrate that if 0.1mM myoinositol is applied to leaves of greenhouse maize, some metabolites that are changed by UV-B are also changed similarly by the chemical treatment. (author)

Alteration of chromophoric dissolved organic matter by solar UV radiation causes rapid changes in bacterial community composition†

Science.gov (United States)

Piccini, Claudia; Conde, Daniel; Pernthaler, Jakob; Sommaruga, Ruben

2010-01-01

We evaluated the effect of photochemical alterations of chromophoric dissolved organic matter (CDOM) on bacterial abundance, activity and community composition in a coastal lagoon of the Atlantic Ocean with high dissolved organic carbon concentration. On two occasions during the austral summer, bacteria-free water of the lagoon was exposed to different regions of the solar spectrum (full solar radiation, UV-A + PAR, PAR) or kept in the dark. Subsequently, dilution cultures were established with bacterioplankton from the lagoon that were incubated in the pre-exposed water for 5 h in the dark. Cell abundance, activity, and community composition of bacterioplankton were assessed before and after incubation in the different treatments. Changes in absorption, fluorescence, and DOC concentration were used as proxies for CDOM photoalteration. We found a significant CDOM photobleaching signal, DOC loss, as well as a stimulation of bacterial activity in the treatments pre-exposed to UV radiation, suggesting increased bioavailability of DOM. Bacterial community analysis by fluorescence in situ hybridization revealed that this stimulation was mainly accompanied by the specific enrichment of Alpha- and Betaproteobacteria. Thus, our results suggest that CDOM photoalteration not only stimulates bacterioplankton growth, but also induces rapid changes in bacterioplankton composition, which can be of relevance for ecosystem functioning, particularly considering present and future changes in the input of terrestrial CDOM to aquatic systems. PMID:19707620

Alteration of chromophoric dissolved organic matter by solar UV radiation causes rapid changes in bacterial community composition.

Science.gov (United States)

Piccini, Claudia; Conde, Daniel; Pernthaler, Jakob; Sommaruga, Ruben

2009-09-01

We evaluated the effect of photochemical alterations of chromophoric dissolved organic matter (CDOM) on bacterial abundance, activity and community composition in a coastal lagoon of the Atlantic Ocean with high dissolved organic carbon concentration. On two occasions during the austral summer, bacteria-free water of the lagoon was exposed to different regions of the solar spectrum (full solar radiation, UV-A+PAR, PAR) or kept in the dark. Subsequently, dilution cultures were established with bacterioplankton from the lagoon that were incubated in the pre-exposed water for 5 h in the dark. Cell abundance, activity, and community composition of bacterioplankton were assessed before and after incubation in the different treatments. Changes in absorption, fluorescence, and DOC concentration were used as proxies for CDOM photoalteration. We found a significant CDOM photobleaching signal, DOC loss, as well as a stimulation of bacterial activity in the treatments pre-exposed to UV radiation, suggesting increased bioavailability of DOM. Bacterial community analysis by fluorescence in situ hybridization revealed that this stimulation was mainly accompanied by the specific enrichment of Alpha- and Betaproteobacteria. Thus, our results suggest that CDOM photoalteration not only stimulates bacterioplankton growth, but also induces rapid changes in bacterioplankton composition, which can be of relevance for ecosystem functioning, particularly considering present and future changes in the input of terrestrial CDOM to aquatic systems.

Effect of solar radiation (UV and visible) at high altitude on CAM-cycling and phenolic compound biosynthesis in Sedum album

International Nuclear Information System (INIS)

Bachereau, F.; Marigo, G.; Asta, J.

1998-01-01

The field experiment was carried out in order to compare the response of a CAM plant, Sedum album L., to solar radiation at a high altitude (2 100 m) with that at a low altitude location with respect to CAM and phenolic content. Treatment sites included (1) sun-exposed, low altitude, (2) sun-exposed, high altitude with different light treatments, including UV-B and UV-B + A screening, and (3) shade at high altitude. After a 70-day treatment period, CAM-cycling and phenolic compound content were analysed, and high altitude treatments were compared to the low altitude control. The sun-exposed low altitude control was characterized by CAM-cycling and a low phenolic compound content during the experiment. In plants transplanted to the high altitude, only the shaded group maintained a CAM-cycling and a phenolic compound content similar to those of the sun-exposed low altitude control. Samples under UV-B and UV-B + A filters showed similar responses, suggesting the absence of a specific UV-A radiation effect. The screening of UV-B or UV-B + A radiation allowed plants to partially maintain a CAM-cycling and induced a decrease in phenolic compound content. These responses under UV filters were, however, intermediate between those observed in sun-exposed and shaded groups. These results demonstrate a specific effect of radiation from both visible (400–800 nm) and UV-B (280–320 nm) bands on both CAM-cycling and phenolic biosynthesis in S. album L. plants. These light-dependent effects are discussed on a physiological basis and a possible interaction between CAM-cycling and phenolic metabolism is suggested. (author)

The global and UV-B radiation over Egypt

OpenAIRE

BASSET, H. A.; KORANY, M. H.

2007-01-01

This work studies the relation between UV-B radiation and global radiation over Egypt. The relationships between the global solar radiation and UV-B radiation at four stations in Egypt have been studied, and linear empirical formulas for estimating UV-B from global radiation at these stations has been deduced. The deduced equations were applied to calculate the UV-B radiation for other stations where measurements were unavailable, using records of global radiation at these stations. Because o...

UV Radiation and the Skin

Directory of Open Access Journals (Sweden)

Timothy Scott

2013-06-01

Full Text Available UV radiation (UV is classified as a “complete carcinogen” because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natural synthesis of vitamin D and endorphins in the skin, therefore UV has complex and mixed effects on human health. Nonetheless, excessive exposure to UV carries profound health risks, including atrophy, pigmentary changes, wrinkling and malignancy. UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma, which together affect more than a million Americans annually. Genetic factors also influence risk of UV-mediated skin disease. Polymorphisms of the melanocortin 1 receptor (MC1R gene, in particular, correlate with fairness of skin, UV sensitivity, and enhanced cancer risk. We are interested in developing UV-protective approaches based on a detailed understanding of molecular events that occur after UV exposure, focusing particularly on epidermal melanization and the role of the MC1R in genome maintenance.

"PROCESS and UVolution: photochemistry experiments in Low Earth Orbit": investigation of the photostability of organic and mineral material exposed to Mars surface UV radiation conditions

Science.gov (United States)

Stalport, Fabien; Guan, Yuan Yong; Noblet, Audrey; Coll, Patrice; Szopa, Cyril; Macari, Frederique; Person, Alain; Chaput, Didier; Raulin, Francois; Cottin, Hervé

The harsh martian environment could explain the lack of organics and minerals such as car-bonates by destroying them: i) no organic molecule has been found at the two different landing sites of the Viking landers within the detection limits of the instruments onboard, ii) to date, no large deposits of carbonates have been detected and their detection is specific of local ar-eas and in very low amounts. In this context several experimental and numerical modelling studies were led to evaluate the possibility for the destruction or evolution of the organics and carbonates under the martian surface environmental conditions. The presence of UV radiation has been proposed to explain the photodecomposition of such material. This is the reason why, to investigate the nature, abundance, and stability of organic and mineral material that could survive under such environmental conditions, we exposed in low Earth orbit organic molecules and carbonates (also biominerals) with martian relevance to solar UV radiation ¿ 200 nm, in the frame of the experiment UVolution, onboard the BIOPAN ESA module which was set outside a Russian Foton automated capsule and exposed to space condition during 12 days in September 2007, and the experiment PROCESS (hervé peux tu rajouter quelques infos sur le temps exact d'exposition stp) which was set outside the International Space Station (ISS). Here, we present results with regard to the impact of solar UV radiation on the targeted molecules. Preliminary results indicate that that no organic sample seems to resist to the solar UV radiation if directly exposed to it. Conversely our results show that the exposed carbonates seem to be stable to the solar UV radiation if directly exposed to it. Moreover, the stability of the biominerals strengthens the interest to explore deeper their potential as life records at Mars. Hence they should be considered as primary targets for in situ analyses during future missions.

Design of nanophotonic, hot-electron solar-blind ultraviolet detectors with a metal-oxide-semiconductor structure

International Nuclear Information System (INIS)

Wang, Zhiyuan; Wang, Xiaoxin; Liu, Jifeng

2014-01-01

Solar-blind ultraviolet (UV) detection refers to photon detection specifically in the wavelength range of 200 nm–320 nm. Without background noises from solar radiation, it has broad applications from homeland security to environmental monitoring. The most commonly used solid state devices for this application are wide band gap (WBG) semiconductor photodetectors (Eg > 3.5 eV). However, WBG semiconductors are difficult to grow and integrate with Si readout integrated circuits (ROICs). In this paper, we design a nanophotonic metal-oxide-semiconductor structure on Si for solar-blind UV detectors. Instead of using semiconductors as the active absorber, we use Sn nano-grating structures to absorb UV photons and generate hot electrons for internal photoemission across the Sn/SiO 2 interfacial barrier, thereby generating photocurrent between the metal and the n-type Si region upon UV excitation. Moreover, the transported hot electron has an excess kinetic energy >3 eV, large enough to induce impact ionization and generate another free electron in the conduction band of n-Si. This process doubles the quantum efficiency. On the other hand, the large metal/oxide interfacial energy barrier (>3.5 eV) also enables solar-blind UV detection by blocking the less energetic electrons excited by visible photons. With optimized design, ∼75% UV absorption and hot electron excitation can be achieved within the mean free path of ∼20 nm from the metal/oxide interface. This feature greatly enhances hot electron transport across the interfacial barrier to generate photocurrent. The simple geometry of the Sn nano-gratings and the MOS structure make it easy to fabricate and integrate with Si ROICs compared to existing solar-blind UV detection schemes. The presented device structure also breaks through the conventional notion that photon absorption by metal is always a loss in solid-state photodetectors, and it can potentially be extended to other active metal photonic devices. (paper)

Environmental benefits of domestic solar energy systems

International Nuclear Information System (INIS)

Kalogirou, Soteris A.

2004-01-01

All nations of the world depend on fossil fuels for their energy needs. However the obligation to reduce CO 2 and other gaseous emissions in order to be in conformity with the Kyoto agreement is the reason behind which countries turn to non-polluting renewable energy sources. In this paper the pollution caused by the burning of fossil fuels is initially presented followed by a study on the environmental protection offered by the two most widely used renewable energy systems, i.e. solar water heating and solar space heating. The results presented in this paper show that by using solar energy, considerable amounts of greenhouse polluting gasses are avoided. For the case of a domestic water heating system, the saving, compared to a conventional system, is about 80% with electricity or Diesel backup and is about 75% with both electricity and Diesel backup. In the case of space heating and hot water system the saving is about 40%. It should be noted, however, that in the latter, much greater quantities of pollutant gasses are avoided. Additionally, all systems investigated give positive and very promising financial characteristics. With respect to life cycle assessment of the systems, the energy spent for manufacture and installation of the solar systems is recouped in about 1.2 years, whereas the payback time with respect to emissions produced from the embodied energy required for the manufacture and installation of the systems varies from a few months to 9.5 years according to the fuel and the particular pollutant considered. Moreover, due to the higher solar contribution, solar water heating systems have much shorter payback times than solar space heating systems. It can, therefore, be concluded that solar energy systems offer significant protection to the environment and should be employed whenever possible in order to achieve a sustainable future

UV-induced carbon monoxide emission from sand and living vegetation

DEFF Research Database (Denmark)

Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

2012-01-01

The global burden of carbon monoxide, CO, is rather uncertain. In this paper we address the potential of UV-induced CO emission by terrestrial surfaces. Real-time measurements of [CO] were made with a cavity enhanced laser connected in closed loop to either an ecosystem chamber or a leaf scale...... chamber. Sand and leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation and the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature, indicating an abiotic process. The emission of CO...... in response to the UV-component of natural solar radiation was also evident at the ecosystem scale. When scaled to the global level, the UV-induced emission of CO by the major types of terrestrial surfaces, living leaves and soil (here represented by sand), amounts up to 28 Tg yr−1. This source has...

Synergistic effect of heat and solar UV on DNA damage and water disinfection of E. coli and bacteriophage MS2.

Science.gov (United States)

Theitler, Dana Jennifer; Nasser, Abid; Gerchman, Yoram; Kribus, Abraham; Mamane, Hadas

2012-12-01

The response of a representative virus and indicator bacteria to heating, solar irradiation, or their combination, was investigated in a controlled solar simulator and under real sun conditions. Heating showed higher inactivation of Escherichia coli compared to the bacteriophage MS2. Heating combined with natural or simulated solar irradiation demonstrated a synergistic effect on the inactivation of E. coli, with up to 3-log difference for 50 °C and natural sun insolation of 2,000 kJ m(-2) (compared to the sum of the separate treatments). Similar synergistic effect was also evident when solar-UV induced DNA damage to E. coli was assessed using the endonuclease sensitive site assay (ESS). MS2 was found to be highly resistant to irradiation and heat, with a slightly synergistic effect observed only at 59 °C and natural sun insolation of 5,580 kJ m(-2). Heat treatment also hindered light-dependent recovery of E. coli making the treatment much more effective.

Solar radiation and tidal exposure as environmental drivers of Enhalus acoroides dominated seagrass meadows.

Directory of Open Access Journals (Sweden)

Richard K F Unsworth

Full Text Available There is strong evidence of a global long-term decline in seagrass meadows that is widely attributed to anthropogenic activity. Yet in many regions, attributing these changes to actual activities is difficult, as there exists limited understanding of the natural processes that can influence these valuable ecosystem service providers. Being able to separate natural from anthropogenic causes of seagrass change is important for developing strategies that effectively mitigate and manage anthropogenic impacts on seagrass, and promote coastal ecosystems resilient to future environmental change. The present study investigated the influence of environmental and climate related factors on seagrass biomass in a large ≈250 ha meadow in tropical north east Australia. Annual monitoring of the intertidal Enhalus acoroides (L.f. Royle seagrass meadow over eleven years revealed a declining trend in above-ground biomass (54% significant overall reduction from 2000 to 2010. Partial Least Squares Regression found this reduction to be significantly and negatively correlated with tidal exposure, and significantly and negatively correlated with the amount of solar radiation. This study documents how natural long-term tidal variability can influence long-term seagrass dynamics. Exposure to desiccation, high UV, and daytime temperature regimes are discussed as the likely mechanisms for the action of these factors in causing this decline. The results emphasise the importance of understanding and assessing natural environmentally-driven change when interpreting the results of seagrass monitoring programs.

Antiradiation UV Vaccine: UV Radiation, Biological effects, lesions and medical management - immune-therapy and immune-protection.

Science.gov (United States)

Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

Key Words: Ultraviolet radiation,Standard Erythema Dose(SED), Minimal Erythema Dose(MED), Sun Burns, Solar Dermatitis, Sun Burned Disease, DNA Damage,Cell Damage, Antiradiation UV Vaccine, Immune-Prophylaxis of Sun Burned Diseases, Immune-Prophylaxis of Sun Burns, Immune-Therapy of Sun-Burned Disease and Sun Burns,Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), Toxic Epidermal Necrolysis(TEN). Introduction: High doses of UV generated by solar source and artificial sources create an exposure of mammals and other species which can lead to ultraviolet(UV)radiation- associated disease (including erythema, epilation, keratitis, etc.). UV radiation belongs to the non-ionizing part of the electromagnetic spectrum and ranges between 100 nm and 400 nm with 100 nm having been chosen arbitrarily as the boundary between non-ionizing and ionizing radiation, however EMR is a spectrum and UV can produce molecular ionization. UV radiation is conventionally categorized into 3 areas: UV-A (>315-400 nm),UV-B (>280-315 nm)and UV-C (>100-280 nm) [IARC,Working Group Reports,2005] An important consequence of stratospheric ozone depletion is the increased transmission of solar ultraviolet (UV)radiation to the Earth's lower atmosphere and surface. Stratospheric ozone levels have been falling, in certain areas, for the past several decades, so current surface ultraviolet-B (UV-B) radiation levels are thought to be close to their modern day maximum. [S.Madronich et al.1998] Overexposure of ultraviolet radiation a major cause of skin cancer including basal cell carcinoma (BCC), squamous cell carcinoma (SCC) { collectively referred to as “non-melanoma" skin cancer (NMSC) and melanoma as well, with skin cancers being the most common cancer in North America. [Armstrong et al. 1993, Gallagher et al. 2005] Methods and Experimental Design: Our experiments and testing of a novel UV “Antiradiation Vaccine” have employed a wide variety of laboratory animals which include : Chinchilla

Transglutaminase involvement in UV-A damage to the eye lens

International Nuclear Information System (INIS)

Weinreb, Orly; Dovrat, A.

1996-01-01

Solar radiation is believed to be one of the major environmental factors involved in lens cataractogenesis. The purpose of the study was to investigate the mechanisms by which UV-A at 365 nm causes damage to the eye lens. Bovine lenses were placed in special culture cells for pre-incubation of 24 hr. The lenses were positioned so that the anterior surface faced the incident UV-A radiation source and were maintained in the cells during irradiation. After irradiation, lens optical quality was monitored throughout the culture period and lens epithelium, cortex and nuclear samples were taken for biochemical analysis. Transglutaminase activity in the lens was affected by the radiation. The activity of transglutaminase in lens epithelium cortex and nucleus increased as a result of the irradiation and then declined towards control levels during the culture period, as the lens recovered from the UV-A damage. Specific lens proteins αB and βB1 crystallins (the enzyme substrates) were analyzed by SDS polyacrylamid gel electrophoreses and immunoblotting with specific antibodies. Seventy-two hours after irradiation of 44.8 J cm -2 UV-A, αB crystallins were affected as was shown by the appearance of aggregation and degradation products. Some protein changes seem to be reversible. It appears that transglutaminase may be involved in the mechanism by which UV-A causes damage to the eye lens. (Author)

Prediction of daily UV-A from daily global solar irradiance using the Ktuv and Kt clearness index; Prediccion de valores diarios de radiacion solar UV-A (295-385 nm) utilizando los indices de transparencia K{sub t}uv y K{sub t} y tecnicas de resdes neuronales artificiales

Energy Technology Data Exchange (ETDEWEB)

Barbero, F. J.; Lopez, G.; Batlles, F. J.

2004-07-01

In this work we compare two methodologies in order to estimate daily UV-A from daily global solar irradiance measurements. The first one is based on standard statistical procedures for relating the daily clearness indices Ktuv and Kt and the relative air mass, whereas the second methodology is based on the novel techniques of artificial neuronal networks. In both cases, we employed data recorded at the radiometric station located at the University of Almeria between 1993 and 1996. Both models are checked against data for years not previously used. (Author)

Polycrystalline diamond film UV detectors for excimer lasers

International Nuclear Information System (INIS)

Ralchenko, V G; Savel'ev, A V; Konov, Vitalii I; Mazzeo, G; Spaziani, F; Conte, G; Polyakov, V I

2006-01-01

Photoresistive metal-semiconductor-metal detectors based on polycrystalline diamond films are fabricated for recording cw and pulsed UV radiation. The detectors have a high spectral selectivity (the UV-to-VIS response ratio is ∼10 5 ) and a temporal resolution of the order of 10 9 s. 'Solar-blind' photostable diamond detectors are promising for applications in UV lithography, laser micromachining, medicine, and space research. (letters)

Environmental simulation testing of solar cell contamination by hydrazine

Science.gov (United States)

Moore, W. W., Jr.

1972-01-01

Test results for thermal vacuum and radiation environment simulation of hydrazine contamination are discussed. Solar cell performance degradation, measured by short circuit current, is presented in correlation with the variations used in environmental parameters.

78 FR 54669 - Draft Environmental Impact Statement for the Proposed RES Americas Moapa Solar Energy Center...

Science.gov (United States)

2013-09-05

... Environmental Impact Statement for the Proposed RES Americas Moapa Solar Energy Center, Clark County, Nevada... environmental impact statement (DEIS) for the proposed RES Americas Moapa Solar Energy Center on the Moapa River... Progress and on the following Web site: www.MoapaSolarEnergyCenterEIS.com . In order to be fully considered...

Loss of inducible photorepair in a frog cell line hypersensitive to solar UV light

International Nuclear Information System (INIS)

Chao, C.C.-K.

1987-01-01

The induction of enzymatic photorepair (EPR) in ICR 2A frog cells and a derived mutant cell line DRP36 hypersensitive to solar UV was studied. Using clonogenic assays, when induced wild-type cells demonstrated an 8-fold increase of EPR the mutant cells displayed a near-background level of inducible EPR. The constitutive EPR in mutant cells, however, was the same as in wild-type cells. A mixed culture of ICR 2A and DRP36 cells showed an intermediate inducible EPR depending upon the cell ratio. Inducible EPR was also detected at the DNA level in wild-type cells, but not in mutant cells. 29 refs.; 2 figs.; 2 tabs

Mir Environmental Effects Payload and Returned Mir Solar Panel Cleanliness

Science.gov (United States)

Harvey, Gale A.; Humes, Donald H.; Kinard, William H.

2000-01-01

The MIR Environmental Effects Payload (MEEP) was attached to the Docking Module of the MIR space station for 18 months during calendar years 1996 and 1997 (March 1996, STS 76 to October 1997, STS 86). A solar panel array with more than 10 years space exposure was removed from the MIR core module in November 1997, and returned to Earth in January, 1998, STS 89. MEEP and the returned solar array are part of the International Space Station (ISS) Risk Mitigation Program. This space flight hardware has been inspected and studied by teams of space environmental effects (SEE) investigators for micrometeoroid and space debris effects, space exposure effects on materials, and electrical performance. This paper reports changes in cleanliness of parts of MEEP and the solar array due to the space exposures. Special attention is given to the extensive water soluble residues deposited on some of the flight hardware surfaces. Directionality of deposition and chemistry of these residues are discussed.

Climatology of UVA and ozone variations and the global solar UV-index

International Nuclear Information System (INIS)

Roy, C.R.; Gies, H.P.; Toomey, S.J.

1996-01-01

Human overexposure to solar ultraviolet radiation (UVR) can result in acute and chronic adverse health effects on both the skin and the eye. Skin cancer (both non-melanoma and malignant melanoma) and cataract impose a huge social and cost burden on many societies throughout the world. Such human health problems can be avoided if the individual reduces their UVR exposure. Unfortunately enlightenment may not help persons who have experienced high episodic exposures during childhood as this appears to be an important causal factor in melanoma. In some countries public educational campaigns have been underway for decades in other countries they are just beginning; the global solar uv-index provides a globally consistent means of reporting or predicting UVR as part of public education on UVR exposure. There are now indications that some of these programs have been effective in halting the climb in melanoma incidence. The UVR, and in particular UVB, reaching the earth's surface varies with both latitude and time (both of the day and year). The transmission of the extraterrestrial radiation through the atmosphere is determined by ozone clouds, aerosols and to a lesser extent, trace gases. In recent decades there has been considerable concern that long-term changes in ozone and perhaps clouds and aerosols may result in changes in the UVB at the earth's surface. (author)

A mechanism for solar ultraviolet flux variability

International Nuclear Information System (INIS)

Schatten, K.H.; Heath, D.F.

1981-01-01

Solar UV emission observed by a filter photometer on Nimbus IV from 1969 to 1973 is examined in an attempt to understand the short term (27 day) and secular variability. Two models are discussed to explain the variations - a calcium plage model and a chromospheric network (faculae and spicule) structure model. Both relate to the remnant magnetic fields of active regions. An association between UV brightenings and the large scale magnetic field has been found consistent with the network model. An increase in UV emittance can be achieved by raising the effective chromospheric temperature closer to a photospheric level. If the Sun's luminosity is constant on these time intervals the enhanced UV radiation could be partially offset by an overall decrease in photospheric temperature as measured by Livingston in visible photospheric profiles. Total solar luminosity may then show less variability, however, the UV to visible luminosity variation may have significant planetary influences. Lockwood and Thompson (1979) report a relation between solar activity and planetary albedos, and Schatten (1979) discussed a long-suspected relationship between solar activity and the Great Red Spot appearance. (orig.)

Solar ultraviolet radiation response of EBT2 Gafchromic, radiochromic film

International Nuclear Information System (INIS)

Butson, Ethan T; Yu, Peter K N; Butson, Martin J

2013-01-01

Measurement of solar ultraviolet (UV) radiation is an important aspect of dosimetry for the improved knowledge of UV exposure and its associated health related issues. EBT2 Gafchromic film has been designed by its manufacturers as an improved tool for ionizing radiation dosimetry. The film is stated as exhibiting a significant reduction in UV response. However, results have shown that when exposed to UV from the ‘bottom side’ i.e. from the thick laminate side, the film exhibits a sensitivity to solar UV radiation which is both measurable and accurate for UV dosimetry. Films were irradiated in this position to known solar UV exposures and results are quantified showing a reproducibility of measurement to within ±7% (1 SD) when compared to calibrated UV meters. With an exposure of 20 J cm −2 broad spectrum solar UV, the films net OD change was found to be 0.248 OD ± 0.021 OD when analysing the results using the red channel region of an Epson V700 desktop scanner. This was compared to 0.0294 OD ± 0.0053 OD change with exposure to the same UV exposure from the top side. This means that solar UV dosimetry can be performed using EBT2 Gafchromic film utilizing the underside of the film for dosimetry. The main advantages of this film type for measurement of UV exposure is the visible colour change and thus easy analysis using a desktop scanner as well as its uniformity in response and its robust physical strength for use in outside exposure situations. (note)

Estimation of surface UV levels based on Meteor-3/TOMS ozone data

Energy Technology Data Exchange (ETDEWEB)

Borisov, Y A [Central Aerological Observatory, Moscow (Russian Federation); Geogdzhaev, I V [Moscow Inst. of Physics and Technology, Moscow (Russian Federation); Khattatov, V U [Central Aerological Observatory, Moscow (Russian Federation)

1996-12-31

The major consequence of ozone layer depletion for the environment is an increase of harmful ultraviolet (UV) radiation on the Earth surface and in the upper ocean. This implies the importance of environmental UV monitoring. Since the direct global monitoring is not currently possible, indirect estimations of surface UV levels may be used based on satellite ozone data (Madronich, S. 1992). Total Ozone Mapping Spectrometer (TOMS) on board the METEOR-3 satellite provided regular set of data for such estimates. During the time of its operation (August, 1991 - December, 1994) the instrument registered several ozone hole events over Antarctica, when ozone levels dropped by as much as 60 % from their unperturbed values. Probably even more alarming ozone depletions were observed over highly populated regions of middle latitudes of northern hemisphere. Radiative transfer modeling was used to convert METEOR-3/TOMS daily ozone values into regional and global maps of biologically active UV. Calculations demonstrate the effect on surface UV levels produced by ozone hole over Antarctica and ozone depletions over the territory of Russia (March, 1994). UV contour lines deviate from the normal appearance which is determined by growing southward solar elevation. UV contour lines are almost perpendicular to the ozone ones in the ozone depletions areas. The 30 % ozone depletion, over Siberia caused more than 30 % increase in noontime erythemal UV levels, which is equivalent to 10-15 degrees southward latitude displacement. Higher UV radiation increases were found in ozone hole over South America (October 1992) equivalent to about 20 degrees southward displacement

Estimation of surface UV levels based on Meteor-3/TOMS ozone data

Energy Technology Data Exchange (ETDEWEB)

Borisov, Y.A. [Central Aerological Observatory, Moscow (Russian Federation); Geogdzhaev, I.V. [Moscow Inst. of Physics and Technology, Moscow (Russian Federation); Khattatov, V.U. [Central Aerological Observatory, Moscow (Russian Federation)

1995-12-31

The major consequence of ozone layer depletion for the environment is an increase of harmful ultraviolet (UV) radiation on the Earth surface and in the upper ocean. This implies the importance of environmental UV monitoring. Since the direct global monitoring is not currently possible, indirect estimations of surface UV levels may be used based on satellite ozone data (Madronich, S. 1992). Total Ozone Mapping Spectrometer (TOMS) on board the METEOR-3 satellite provided regular set of data for such estimates. During the time of its operation (August, 1991 - December, 1994) the instrument registered several ozone hole events over Antarctica, when ozone levels dropped by as much as 60 % from their unperturbed values. Probably even more alarming ozone depletions were observed over highly populated regions of middle latitudes of northern hemisphere. Radiative transfer modeling was used to convert METEOR-3/TOMS daily ozone values into regional and global maps of biologically active UV. Calculations demonstrate the effect on surface UV levels produced by ozone hole over Antarctica and ozone depletions over the territory of Russia (March, 1994). UV contour lines deviate from the normal appearance which is determined by growing southward solar elevation. UV contour lines are almost perpendicular to the ozone ones in the ozone depletions areas. The 30 % ozone depletion, over Siberia caused more than 30 % increase in noontime erythemal UV levels, which is equivalent to 10-15 degrees southward latitude displacement. Higher UV radiation increases were found in ozone hole over South America (October 1992) equivalent to about 20 degrees southward displacement

TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

Science.gov (United States)

Zempila, Melina-Maria; van Geffen, Jos H. G. M.; Taylor, Michael; Fountoulakis, Ilias; Koukouli, Maria-Elissavet; van Weele, Michiel; van der A, Ronald J.; Bais, Alkiviadis; Meleti, Charikleia; Balis, Dimitrios

2017-06-01

This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE) erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4) UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU)-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh), in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN) was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990) and with a very low bias (0.000 to 0.011 in absolute units) proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES) UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5° (lat × long) grid cells. TEMIS

TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

Directory of Open Access Journals (Sweden)

M.-M. Zempila

2017-06-01

Full Text Available This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4 UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh, in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990 and with a very low bias (0.000 to 0.011 in absolute units proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5�

environmental/climatic effect on stand-alone solar energy supply

African Journals Online (AJOL)

This paper investigates the climatic effects and environmental variations on the perfor- mance of a ... inter-connected arrays due to shades from clouds, tress and ... Modeling of Solar Module .... needs. The earth revolves around the sun in an.

The cloud effects on UV irradiance modeled in Antarctica

International Nuclear Information System (INIS)

Rafanelli, C.; Anav, A.; Ciattaglia, L.; Di Menno, I.; Di Menno, M.; Araujo, J.; Ochoa, H.; Rodriguez, H.

2004-01-01

Full text: The measurement of solar UV radiation in Antarctica is very important in order to obtain information about Ozone level, and many spectro radiometers are installed in the area to perform this task. Usually, their use is very difficult in harsh environment like Southern polar regions, and several multichannel radiometers have been installed. The evaluation of the irradiance and total ozone levels are done using analytical models. A new semi-analytical method to estimate the solar UV irradiance at ground, named WL4UV, was developed. Using spectral irradiance values at 4 selected wavelengths in the UV-B and UV-A regions (305, 320, 340 and 380 nm), the solar UV irradiance at ground is evaluated with low percent of error. The applicability of the method has been tested for clear sky but such conditions are not common in Antarctic. This work investigate the applicability of the WL4UV model under cloudy sky conditions. The 4 irradiance necessary for the model were selected from spectrophotometer Brewer measurements carried out in the Argentinean Belgrano II base (77 degrees 52' S and 34 degrees 38' W). Other tests using spectrophotometers, Brewer and SUV 100, located in Ushuaia, (54 degrees 50' S and 68 degrees 19' W), were also too. This project was funded by the PNRA, IIA-DNA and CADIC for funding and supporting the activities. They thank also all the Brewer operators that in these years spent their time in the management of the instrument. Last but not the least they thank all IIA-DNA personnel for the professional help they put in carrying out the activities in all these years. (author)

Hope and challenge: the importance of ultraviolet (UV) radiation for cutaneous vitamin D synthesis and skin cancer.

Science.gov (United States)

Reichrath, Jörg; Reichrath, Sandra

2012-01-01

Abstract Solar ultraviolet (UV)-radiation is the most important environmental risk factor for the development of non-melanoma skin cancer (most importantly basal and squamous cell carcinomas), that represent the most common malignancies in Caucasian populations. To prevent these malignancies, public health campaigns were developed to improve the awareness of the general population of the role of UV-radiation. The requirements of vitamin D is mainly achieved by UV-B-induced cutaneous photosynthesis, and the vitamin D-mediated positive effects of UV-radiation were not always adequately considered in these campaigns; a strict "no sun policy" might lead to vitamin D-deficiency. This dilemma represents a serious problem in many populations, for an association of vitamin D-deficiency and multiple independent diseases has been convincingly demonstrated. It is crucial that guidelines for UV-exposure (e.g. in skin cancer prevention campaigns) consider these facts and give recommendations how to prevent vitamin D-deficiency. In this review, we analyze the present literature to help developing well-balanced guidelines on UV-protection that ensure an adequate vitamin D-status without increasing the risk to develop UV-induced skin cancer.

Long-term visual health risks from solar ultraviolet radiation

International Nuclear Information System (INIS)

Waxler, M.

1987-01-01

Ocular exposure to the ultraviolet radiation (UV) contained in sunlight may result in long-term visual health problems. UV plays a role in the etiology of cataracts and possibly in the etiology of visual impairments associated with solar retinopathy, retinopathy of prematurity, ocular aging, cystoid macular edema, retinitis pigmentosa, and senile macular degeneration. The exact does relationships between known UV bioeffects and these ocular problems is, however, uncertain. Thus, there are questions about the extent to which protective measures should be taken to reduce UV exposure of the eye. This paper identifies the long-term visual health problems potentially associated with ocular exposure to solar UV; proposes worst-case assumptions for the role of solar UV in these visual problems; and recommends protective measures based on damage thresholds and worst-case assumptions

Systemic administration of the apocarotenoid bixin protects skin against solar UV-induced damage through activation of NRF2.

Science.gov (United States)

Tao, Shasha; Park, Sophia L; Rojo de la Vega, Montserrat; Zhang, Donna D; Wondrak, Georg T

2015-12-01

Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photodamage and carcinogenesis, and an urgent need exists for improved molecular photoprotective strategies different from (or synergistic with) photon absorption. Recent studies suggest a photoprotective role of cutaneous gene expression orchestrated by the transcription factor NRF2 (nuclear factor-E2-related factor 2). Here we have explored the molecular mechanism underlying carotenoid-based systemic skin photoprotection in SKH-1 mice and provide genetic evidence that photoprotection achieved by the FDA-approved apocarotenoid and food additive bixin depends on NRF2 activation. Bixin activates NRF2 through the critical Cys-151 sensor residue in KEAP1, orchestrating a broad cytoprotective response in cultured human keratinocytes as revealed by antioxidant gene expression array analysis. Following dose optimization studies for cutaneous NRF2 activation by systemic administration of bixin, feasibility of bixin-based suppression of acute cutaneous photodamage from solar UV exposure was investigated in Nrf2(+/+) versus Nrf2(-/-) SKH-1 mice. Systemic administration of bixin suppressed skin photodamage, attenuating epidermal oxidative DNA damage and inflammatory responses in Nrf2(+/+) but not in Nrf2(-/-) mice, confirming the NRF2-dependence of bixin-based cytoprotection. Taken together, these data demonstrate feasibility of achieving NRF2-dependent cutaneous photoprotection by systemic administration of the apocarotenoid bixin, a natural food additive consumed worldwide. Copyright © 2015 Elsevier Inc. All rights reserved.

Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

DEFF Research Database (Denmark)

Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

2011-01-01

, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

Different atmospheric parameters influence on spectral UV radiation (measurements and modelling)

Energy Technology Data Exchange (ETDEWEB)

Chubarova, N Y [Moscow State Univ. (Russian Federation). Meteorological Observatory; Krotkov, N A [Maryland Univ., MD (United States). JCESS/Meteorology Dept.; Geogdzhaev, I V; Bushnev, S V; Kondranin, T V [SUMGF/MIPT, Dolgoprudny (Russian Federation); Khattatov, V U [Central Aerological Observatory, Dolgoprudny (Russian Federation)

1996-12-31

The ultraviolet (UV) radiation plays a vital role in the biophysical processes despite its small portion in the total solar flux. UV radiation is subject to large variations at the Earth surface depending greatly on solar elevation, ozone and cloud amount, aerosols and surface albedo. The analysis of atmospheric parameters influence is based on the spectral archive data of three spectral instruments: NSF spectroradiometer (Barrow network) (NSF Polar Programs UV Spectroradiometer Network 1991-1992,1992), spectrophotometer (SUVS-M) of Central Aerological Observatory CAO, spectroradiometer of Meteorological Observatory of the Moscow State University (MO MSU) and model simulations based on delta-Eddington approximation

Different atmospheric parameters influence on spectral UV radiation (measurements and modelling)

Energy Technology Data Exchange (ETDEWEB)

Chubarova, N.Y. [Moscow State Univ. (Russian Federation). Meteorological Observatory; Krotkov, N.A. [Maryland Univ., MD (United States). JCESS/Meteorology Dept.; Geogdzhaev, I.V.; Bushnev, S.V.; Kondranin, T.V. [SUMGF/MIPT, Dolgoprudny (Russian Federation); Khattatov, V.U. [Central Aerological Observatory, Dolgoprudny (Russian Federation)

1995-12-31

The ultraviolet (UV) radiation plays a vital role in the biophysical processes despite its small portion in the total solar flux. UV radiation is subject to large variations at the Earth surface depending greatly on solar elevation, ozone and cloud amount, aerosols and surface albedo. The analysis of atmospheric parameters influence is based on the spectral archive data of three spectral instruments: NSF spectroradiometer (Barrow network) (NSF Polar Programs UV Spectroradiometer Network 1991-1992,1992), spectrophotometer (SUVS-M) of Central Aerological Observatory CAO, spectroradiometer of Meteorological Observatory of the Moscow State University (MO MSU) and model simulations based on delta-Eddington approximation

From UV Protection to Protection in the Whole Spectral Range of the Solar Radiation: New Aspects of Sunscreen Development.

Science.gov (United States)

Zastrow, Leonhard; Meinke, Martina C; Albrecht, Stephanie; Patzelt, Alexa; Lademann, Juergen

2017-01-01

Sunscreens have been constantly improving in the past few years. Today, they provide an efficient protection not only in the UVB but also in the UVA spectral region of the solar radiation. Recently it could be demonstrated that 50% of all free radicals induced in the skin due to solar radiation are formed in the visible and infrared spectral region. The good protective efficacy of sunscreens in the UV region prompts people to stay much longer in the sun than if they had left their skin unprotected. However, as no protection in the visible and infrared spectral region is provided, high amounts of free radicals are induced here that could easily exceed the critical radical concentration. This chapter describes how the effect of sunscreens can be extended to cover also the visible and infrared spectral region of the solar radiation by adding pigments and antioxidants with high radical protection factors to the sunscreen formulations.

Regional variations in the health, environmental, and climate benefits of wind and solar generation

Science.gov (United States)

Siler-Evans, Kyle; Azevedo, Inês Lima; Morgan, M. Granger; Apt, Jay

2013-01-01

When wind or solar energy displace conventional generation, the reduction in emissions varies dramatically across the United States. Although the Southwest has the greatest solar resource, a solar panel in New Jersey displaces significantly more sulfur dioxide, nitrogen oxides, and particulate matter than a panel in Arizona, resulting in 15 times more health and environmental benefits. A wind turbine in West Virginia displaces twice as much carbon dioxide as the same turbine in California. Depending on location, we estimate that the combined health, environmental, and climate benefits from wind or solar range from $10/MWh to $100/MWh, and the sites with the highest energy output do not yield the greatest social benefits in many cases. We estimate that the social benefits from existing wind farms are roughly 60% higher than the cost of the Production Tax Credit, an important federal subsidy for wind energy. However, that same investment could achieve greater health, environmental, and climate benefits if it were differentiated by region. PMID:23798431

Regional variations in the health, environmental, and climate benefits of wind and solar generation.

Science.gov (United States)

Siler-Evans, Kyle; Azevedo, Inês Lima; Morgan, M Granger; Apt, Jay

2013-07-16

When wind or solar energy displace conventional generation, the reduction in emissions varies dramatically across the United States. Although the Southwest has the greatest solar resource, a solar panel in New Jersey displaces significantly more sulfur dioxide, nitrogen oxides, and particulate matter than a panel in Arizona, resulting in 15 times more health and environmental benefits. A wind turbine in West Virginia displaces twice as much carbon dioxide as the same turbine in California. Depending on location, we estimate that the combined health, environmental, and climate benefits from wind or solar range from $10/MWh to $100/MWh, and the sites with the highest energy output do not yield the greatest social benefits in many cases. We estimate that the social benefits from existing wind farms are roughly 60% higher than the cost of the Production Tax Credit, an important federal subsidy for wind energy. However, that same investment could achieve greater health, environmental, and climate benefits if it were differentiated by region.

Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

DEFF Research Database (Denmark)

Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, Helge

2011-01-01

Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination......, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

You, me and UV under the sun in South Africa

CSIR Research Space (South Africa)

Wright, C

2009-01-01

Full Text Available This article asks just how harmful are our solar UV rays? It explains what previous researches tell us about how much UV radiation our children are likely to receive and what are the health risks....

Formation of the UV Spectrum of Molecular Hydrogen in the Sun

Science.gov (United States)

Jaeggli, S. A.; Judge, P. G.; Daw, A. N.

2018-03-01

Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in particular regions, selectively excited by a bright UV transition region and chromospheric lines. We test the conditions under which H2 emission can originate by studying non-LTE models, sampling a broad range of temperature stratifications and radiation conditions. Stratification plays the dominant role in determining the population densities of H2, which forms in greatest abundance near the continuum photosphere. However, opacity due to the photoionization of Si and other neutrals determines the depth to which UV radiation can penetrate to excite the H2. Thus the majority of H2 emission forms in a narrow region, at about 650 km in standard one-dimensional (1D) models of the quiet Sun, near the τ = 1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures. A detailed comparison to observations from 1205 to 1550 Å is presented, and the success of this 1D approach to modeling solar UV H2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.

Occupational Exposure to Solar Radiation at Different Latitudes and Pterygium: A Systematic Review of the Last 10 Years of Scientific Literature

Directory of Open Access Journals (Sweden)

Alberto Modenese

2017-12-01

Full Text Available Pterygium is a chronic eye disease: among its recognized risk factors there is long-term exposure to ultraviolet (UV radiation. The Sun is the main source of UV exposure: according to the World Health Organization, the Population Attributable Fraction of pterygium due to solar radiation (SR is 42–74%. Outdoor work can deeply influence the eye exposure to solar UV rays, but, despite this, pterygium is currently not adequately considered as a possible occupational disease in this working category, at least in Europe. For this reason, we performed a systematic review of the scientific literature published in the last ten years (2008–2017 considering the role of outdoor work as a risk factor for pterygium, in order to give new support for the prevention of this UV related disease in workers. We identified 29 relevant papers. Our results show that pterygium prevalence highly increased with latitude and mean annual UV index, and outdoor work is one of the most relevant risk factors, as well as age and male sex, both in high risk and in moderate risk World areas considering the environmental UV levels. Accordingly, pterygium occurring in outdoor workers should be considered an occupational disease. Moreover, our findings clearly support the need of further research on more effective prevention of the occupational risk related to long-term solar radiation exposure of the eye.

Effects of solar ultraviolet radiation on tropical algal communities

International Nuclear Information System (INIS)

Santas, R.

1989-01-01

This study assessed some of the effects of solar ultraviolet (UV) radiation ion coral reef algal assemblages. The first part of the investigation was carried out under controlled laboratory conditions in the coral reef microcosm at the National Museum of Natural History in Washington, D.C., while a field counterpart was completed at the Smithsonian Institution's marine station on Grand Turk, Turks and Caicos Islands, in the eastern Caribbean. The study attempted to separate the effects of UV-A from those of UV-B. In the laboratory, algal turf assemblages exposed to simulated solar UV radiation produced 55.1% less biomass than assemblages that were not exposed to UV. Assemblages not exposed to UV were dominated by Ectocarpus rhodochondroides, whereas in the assemblage developing under high UV radiation, Enteromorpha prolifera and eventually Schizothrix calcicola dominated. Lower UV-B irradiances caused a proportional reduction in biomass production and had less pronounced effects on species composition. UV-A did not have any significant effects on either algal turf productivity or community structure. In the field, assemblages exposed to naturally occurring solar UV supported a biomass 40% lower than that of assemblages protected from UV-B exposure. Once again, UV-A did not inhibit algal turf productivity

Long term variations in erythema effective solar UV at Chilton, UK, from 1991 to 2015.

Science.gov (United States)

Hooke, R J; Higlett, M P; Hunter, N; O'Hagan, J B

2017-11-08

In this paper erythema effective UV radiant exposure data from the PHE solar network Chilton site for the 25 year period from 1991 to 2015 are presented. The year with the highest average daily erythema effective radiant exposure was 2003 at 1577 J m -2 and the year with the lowest average daily radiant exposure was 2010 at 1149 J m -2 . Overall, the average daily radiant exposure per year ranged from 5655 J m -2 to 9.98 J m -2 with the average being 1306 J m -2 . A preliminary analysis of the data set is carried out. A statistically significant (p = 0.01) increase in annual radiant exposure of 4.4% per year was observed from 1991-1995. Thereafter a small decrease in annual erythema effective radiant exposure of 0.8% (p = 0.002) per year was observed from 1995-2015 with a slightly faster rate of decrease from 2000-2015 of 1.0% (p = 0.007) per year. In terms of seasonal analyses, a statistically significant increase in erythema effective UV radiant exposure of 5.1% (p = 0.02) per year in the summer during 1991-1995 has been found along with small decreases in spring and summer during 1995-2015 (-1.0%; p = 0.01 and -0.7%; p = 0.01 respectively) and 2000-2015 (-1.1%; p = 0.03 and -1.2%; p = 0.003 respectively). The data suggest that the erythema effective UV dose available for impacting public health has been decreasing in recent years.

Comparison of the Changes in the Visible and Infrared Irradiance Observed by the SunPhotometers on EURECA to the UARS Total Solar and UV Irradiances

Science.gov (United States)

Pap, Judit

1995-01-01

Solar irradiance in the near-UV (335 nm), visible (500 nm) and infrared (778 nm) spectral bands has been measured by the SunPhotometers developed at the World Radiation Center, Davos, Switzerland on board the European Retrievable Carrier between August 1992 and May 1993. Study of the variations in the visible and infrared irradiance is important for both solar and atmospheric physics. The purpose of this paper is to examine the temporal variations observed in the visible and infrared spectral bands after eliminating the trend in the data mainly related to instrument degradation. The effect of active regions in these spectral irradiances is clearly resolved. Variations in the visible and infrared irradiances are compared to total solar irradiance observed by the SOVA2 radiometer on the EURECA platform and by the ACRIMII radiometer on UARS as well as to UV observations of the UARS and NOAA9 satellites. The space-borne spectral irradiance observations are compared to the photometric sunspot deficit and CaII K irradiance measured at the San Fernando Observatory, California State University at Northridge in order to study the effect of active regions in detail.

Combined Contamination and Space Environmental Effects on Solar Cells and Thermal Control Surfaces

Science.gov (United States)

Dever, Joyce A.; Bruckner, Eric J.; Scheiman, David A.; Stidham, Curtis R.

1994-01-01

For spacecraft in low Earth orbit (LEO), contamination can occur from thruster fuel, sputter contamination products and from products of silicone degradation. This paper describes laboratory testing in which solar cell materials and thermal control surfaces were exposed to simulated spacecraft environmental effects including contamination, atomic oxygen, ultraviolet radiation and thermal cycling. The objective of these experiments was to determine how the interaction of the natural LEO environmental effects with contaminated spacecraft surfaces impacts the performance of these materials. Optical properties of samples were measured and solar cell performance data was obtained. In general, exposure to contamination by thruster fuel resulted in degradation of solar absorptance for fused silica and various thermal control surfaces and degradation of solar cell performance. Fused silica samples which were subsequently exposed to an atomic oxygen/vacuum ultraviolet radiation environment showed reversal of this degradation. These results imply that solar cells and thermal control surfaces which are susceptible to thruster fuel contamination and which also receive atomic oxygen exposure may not undergo significant performance degradation. Materials which were exposed to only vacuum ultraviolet radiation subsequent to contamination showed slight additional degradation in solar absorptance.

Solar energy solutions for an environmentally sustainable world

International Nuclear Information System (INIS)

Morozov, A.I.; Pustovitov, V.D.

1992-01-01

The United Nations Conference of Environment and Development has focused the world's attention on the complex relationship between the environment and economic development. The essence of this relationship, and the emerging theme of UNCED, is the concept of sustainability. Sustainable economic development improves quality of life and raises standards of living by using the Earth's resources in a way that ensures that they are continually renewed, and will continue to support future generations. This is the subject of this report. While energy resources are essential to economic development, the authors current patterns of energy use are not sustainable. Reliance on fossil fuels, nuclear energy, and large-scale hydroelectric projects has contributed to serious environmental problems, including atmospheric pollution, loss of land productivity, loss of biological diversity, ocean and fresh water pollution, and hazardous waste generation. Thus, if they are to achieve sustainability in their patterns of energy consumption, it is imperative that they bring about a rapid and widespread transition to the utilization of environmentally sound energy sources and technologies. Solar energy technologies are environmentally sound, socially beneficial, and economically practical. They have been proven in a wide variety of applications around the world. The barriers to the widespread implementation of solar technologies are no longer technical, but rather social, economic, and political. These barriers can and must be removed

UV-induced N2O emission from plants

Science.gov (United States)

Bruhn, Dan; Albert, Kristian R.; Mikkelsen, Teis N.; Ambus, Per

2014-12-01

Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2h-1, mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

Simulated Space Environmental Effects on Thin Film Solar Array Components

Science.gov (United States)

Finckenor, Miria; Carr, John; SanSoucie, Michael; Boyd, Darren; Phillips, Brandon

2017-01-01

The Lightweight Integrated Solar Array and Transceiver (LISA-T) experiment consists of thin-film, low mass, low volume solar panels. Given the variety of thin solar cells and cover materials and the lack of environmental protection typically afforded by thick coverglasses, a series of tests were conducted in Marshall Space Flight Center's Space Environmental Effects Facility to evaluate the performance of these materials. Candidate thin polymeric films and nitinol wires used for deployment were also exposed. Simulated space environment exposures were selected based on SSP 30425 rev. B, "Space Station Program Natural Environment Definition for Design" or AIAA Standard S-111A-2014, "Qualification and Quality Requirements for Space Solar Cells." One set of candidate materials were exposed to 5 eV atomic oxygen and concurrent vacuum ultraviolet (VUV) radiation for low Earth orbit simulation. A second set of materials were exposed to 1 MeV electrons. A third set of samples were exposed to 50, 100, 500, and 700 keV energy protons, and a fourth set were exposed to >2,000 hours of near ultraviolet (NUV) radiation. A final set was rapidly thermal cycled between -55 and +125degC. This test series provides data on enhanced power generation, particularly for small satellites with reduced mass and volume resources. Performance versus mass and cost per Watt is discussed.

UV exposure in cars.

Science.gov (United States)

Moehrle, Matthias; Soballa, Martin; Korn, Manfred

2003-08-01

There is increasing knowledge about the hazards of solar and ultraviolet (UV) radiation to humans. Although people spend a significant time in cars, data on UV exposure during traveling are lacking. The aim of this study was to obtain basic information on personal UV exposure in cars. UV transmission of car glass samples, windscreen, side and back windows and sunroof, was determined. UV exposure of passengers was evaluated in seven German middle-class cars, fitted with three different types of car windows. UV doses were measured with open or closed windows/sunroof of Mercedes-Benz E 220 T, E 320, and S 500, and in an open convertible car (Mercedes-Benz CLK). Bacillus subtilis spore film dosimeters (Viospor) were attached to the front, vertex, cheeks, upper arms, forearms and thighs of 'adult' and 'child' dummies. UV wavelengths longer than >335 nm were transmitted through car windows, and UV irradiation >380 nm was transmitted through compound glass windscreens. There was some variation in the spectral transmission of side windows according to the type of glass. On the arms, UV exposure was 3-4% of ambient radiation when the car windows were shut, and 25-31% of ambient radiation when the windows were open. In the open convertible car, the relative personal doses reached 62% of ambient radiation. The car glass types examined offer substantial protection against short-wave UV radiation. Professional drivers should keep car windows closed on sunny days to reduce occupational UV exposure. In individuals with polymorphic light eruption, produced by long-wave UVA, additional protection by plastic films, clothes or sunscreens appears necessary.

Radiative flux calculations at UV and visible wavelengths

International Nuclear Information System (INIS)

Grossman, A.S.; Grant, K.E.; Wuebbles, D.J.

1993-10-01

A radiative transfer model to calculate the short wavelength fluxes at altitudes between 0 and 80 km has been developed at LLNL. The wavelength range extends from 175--735 nm. This spectral range covers the UV-B wavelength region, 250--350 nm, with sufficient resolution to allow comparison of UV-B measurements with theoretical predictions. Validation studies for the model have been made for both UV-B ground radiation calculations and tropospheric solar radiative forcing calculations for various ozone distributions. These studies indicate that the model produces results which agree well with respect to existing UV calculations from other published models

Climate hypersensitivity to solar forcing?

Directory of Open Access Journals (Sweden)

W. Soon

2000-05-01

Full Text Available We compare the equilibrium climate responses of a quasi-dynamical energy balance model to radiative forcing by equivalent changes in CO2, solar total irradiance (Stot and solar UV (SUV. The response is largest in the SUV case, in which the imposed UV radiative forcing is preferentially absorbed in the layer above 250 mb, in contrast to the weak response from global-columnar radiative loading by increases in CO2 or Stot. The hypersensitive response of the climate system to solar UV forcing is caused by strongly coupled feedback involving vertical static stability, tropical thick cirrus ice clouds and stratospheric ozone. This mechanism offers a plausible explanation of the apparent hypersensitivity of climate to solar forcing, as suggested by analyses of recent climatic records. The model hypersensitivity strongly depends on climate parameters, especially cloud radiative properties, but is effective for arguably realistic values of these parameters. The proposed solar forcing mechanism should be further confirmed using other models (e.g., general circulation models that may better capture radiative and dynamical couplings of the troposphere and stratosphere.Key words: Meteorology and atmospheric dynamics (climatology · general or miscellaneous · Solar physics · astrophysics · and astronomy (ultraviolet emissions

Effect of UV irradiation on cutaneous cicatrices

DEFF Research Database (Denmark)

Due, Eva; Rossen, Kristian; Sorensen, Lars Tue

2007-01-01

The aim of this study was to examine the effect of ultraviolet (UV) irradiation on human cutaneous cicatrices. In this randomized, controlled study, dermal punch biopsy wounds served as a wound healing model. Wounds healed by primary or second intention and were randomized to postoperative solar UV...... postoperatively, UV-irradiated cicatrices healing by second intention: (i) were significantly pointed out as the most disfiguring; (ii) obtained significantly higher scores of colour, infiltration and cicatrix area; and (iii) showed significantly higher increase in skin-reflectance measurements of skin......-pigmentation vs. non-irradiated cicatrices. No histological, immunohistochemical or biochemical differences were found. In conclusion, postoperative UV exposure aggravates the clinical appearance of cicatrices in humans....

Depletion of stratospheric ozone over the Antarctic and Arctic: Responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview

International Nuclear Information System (INIS)

Rozema, Jelte; Boelen, Peter; Blokker, Peter

2005-01-01

Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution. - Polar plant responses to UV-B may be different in the Arctic than Antarctic regions

Comparative analysis of concentrating solar power and photovoltaic technologies: Technical and environmental evaluations

International Nuclear Information System (INIS)

Desideri, U.; Zepparelli, F.; Morettini, V.; Garroni, E.

2013-01-01

Highlights: ► Life cycle was assessed for both concentrated solar power and photovoltaic systems. ► The PV plant has a higher environmental impact than the CSP plant. ► The Global Warming Potential is lower for the CSP than for the PV plant. ► The energy payback time is lower for the CSP than for the PV plant. -- Abstract: Solar energy is an important alternative energy source to fossil fuels and theoretically the most available energy source on the earth. Solar energy can be converted into electric energy by using two different processes: by means of thermodynamic cycles and the photovoltaic conversion. Solar thermal technologies, sometimes called thermodynamic solar technologies, operating at medium (about 500 °C) and high temperatures (about 1000 °C), have recently attracted a renewed interest and have become one of the most promising alternatives in the field of solar energy utilization. Photovoltaic conversion is very interesting, although still quite expensive, because of the absence of moving components and the reduced operating and management costs. The main objectives of the present work are: •to carry out comparative technical evaluations on the amount of electricity produced by two hypothetical plants, located on the same site, for which a preliminary design was made: a solar thermal power plant with parabolic trough collectors and a photovoltaic plant with a single-axis tracking system; •to carry out a comparative analysis of the environmental impact derived from the processes of electricity generation during the whole life cycle of the two hypothetical power plants. First a technical comparison between the two plants was made assuming that they have the same nominal electric power and then the same total covered surface. The methodology chosen to evaluate the environmental impact associated with the power plants is the Life Cycle Assessment (LCA). It allows to analyze all the phases of the life cycle of the plants, from the extraction of

UV filters for lighting of plants

Energy Technology Data Exchange (ETDEWEB)

Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H.K.; Payer, H.D. [GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany)

1994-12-31

Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The ageing of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In any case chamber experiments require a careful selection of the filter material used and must be accompanied by a continuous UV-B monitoring.

The effect of ultraviolet (UV)-B radiation on primary producers

International Nuclear Information System (INIS)

Germ, M.

2003-01-01

Ozone layer in stratosphere is thinning and consequently UV-B radiation on the Earth surface is increasing. Although there is a small portion of UV-B radiation in the solar radiation, it has strong influence on organisms. Targets of UV-B radiation and protective mechanisms in primary producers are described. In the framework of the international project we studied the effect of UV-B radiation on blue-greens, algae, mosses, lichens and vascular plants on the National Institute of Biology

Effluents treatment by solar photocatalysis; Tratamiento de efluentes con fotocatalisis solar

Energy Technology Data Exchange (ETDEWEB)

Blanco, J; Malato, S; Richter, C [Plataforma Solar de almeria, Almeria (Spain); Carmona, F; Martinez, F [Deretil, Almeria (Spain)

1996-12-31

A solar photocatalytic system is being developed at the Plataforma Solar De Almeria to destroy organic contaminants in water. Test with common water contaminants were conducted at the Solar Detoxification loop with real sun light and large quantities of water flowing through glass tubes were the solar UV light is concentrated. Experiments at this scale provide verification of laboratory studies and allow the design and operation of real preindustrial detoxification systems. (Author)

Soybean resistance to stink bugs (Nezara viridula and Piezodorus guildinii) increases with exposure to solar UV-B radiation and correlates with isoflavonoid content in pods under field conditions.

Science.gov (United States)

Zavala, Jorge A; Mazza, Carlos A; Dillon, Francisco M; Chludil, Hugo D; Ballaré, Carlos L

2015-05-01

Solar UV-B radiation (280-315 nm) has a significant influence on trophic relationships in natural and managed ecosystems, affecting plant-insect interactions. We explored the effects of ambient UV-B radiation on the levels of herbivory by stink bugs (Nezara viridula and Piezodorus guildinii) in field-grown soybean crops. The experiments included two levels of UV-B radiation (ambient and attenuated UV-B) and four soybean cultivars known to differ in their content of soluble leaf phenolics. Ambient UV-B radiation increased the accumulation of the isoflavonoids daidzin and genistin in the pods of all cultivars. Soybean crops grown under attenuated UV-B had higher numbers of unfilled pods and damaged seeds than crops grown under ambient UV-B radiation. Binary choice experiments with soybean branches demonstrated that stink bugs preferred branches of the attenuated UV-B treatment. We found a positive correlation between percentage of undamaged seeds and the contents of daidzin and genistin in pods. Our results suggest that constitutive and UV-B-induced isoflavonoids increase plant resistance to stink bugs under field conditions. © 2014 John Wiley & Sons Ltd.

UV-B radiation and photosynthetic irradiance acclimate eggplant for outdoor exposure

International Nuclear Information System (INIS)

Latimer, J.G.; Mitchell, G.A.

1987-01-01

Treatment of greenhouse-grown eggplant (Solanum melongena L. var. esculentum Nees. 'Burpee's Black Beauty') seedlings with supplemental photosynthetically active radiation from cool-white fluorescent lamps increased growth of plants subsequently transferred outdoors relative to growth of plants that received no supplemental radiation or were shaded to 45% of solar irradiation in the greenhouse before transfer outdoors. Eggplant seedlings transferred outdoors were placed under plastic tarps either to provide relative protection from solar ultraviolet-B (UV-B) radiation (280-315 nm) using Mylar film or to allow exposure to UV-B using cellulose acetate. Protection of seedlings from UV-B radiation resulted in greater leaf expansion than for UV-B-exposed seedlings, but no change in leaf or shoot dry weight occurred after 9 days of treatment. Specific leaf weight increased in response to UV-B exposure outdoors. Exposure of eggplant to UV-B radiation from fluorescent sunlamps in the greenhouse also decreased leaf expansion and leaf and shoot dry weight gain after 5 days of treatment. However, there were no differences in leaf or shoot dry weight relative to control plants after 12 days of UV-B treatment, indicating that UV-B treated plants had acclimated to the treatment and actually had caught up with non-UV-B-irradiated plants in terms of growth

Water decontamination by solar photocatalysis. Descontaminacion de aguas residuales mediante fotocatalisis solar

Energy Technology Data Exchange (ETDEWEB)

Blanco Galvez, J; Malato Rodriguez, S

1993-01-01

A solar photocatalytic system is being developed at the Plataforma Solar de Almeria to destroy organic contaminants in water. Test with common water contaminants were conducted at the Solar Detoxification Loop with real sunlight and large quantities of water flowing through glass tubes were the solar UV light is concentrated. Experiments at this scale provide verification of laboratory studies and allow the design and operation of real preindustrial detoxification systems. (Author)

75 FR 54177 - Notice of Availability of Draft Environmental Impact Statement for the Tonopah Solar Energy...

Science.gov (United States)

2010-09-03

... Statement for the Tonopah Solar Energy Crescent Dunes Solar Energy Project, Nye County, NV AGENCY: Bureau of... Environmental Impact Statement (EIS) for the Crescent Dunes Solar Energy Project, Nye County, Nevada, and by... considered, the BLM must receive written comments on the Crescent Dunes Solar Energy Project Draft EIS within...

Environmental Survey preliminary report, Solar Energy Research Institute, Golden, Colorado

Energy Technology Data Exchange (ETDEWEB)

1988-10-01

This report presents the preliminary findings of the first phase of the Environmental Survey of the US Department of Energy's (DOE) Solar Energy Research Institute (SERI), conducted December 14 through 18, 1987. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. The team includes outside experts supplied by private contractors. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with SERI. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. The on-site phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at SERI, and interviews with site personnel. 33 refs., 22 figs., 21 tabs.

Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

Science.gov (United States)

Lee, Y. G.; Koo, J. H.

2015-12-01

Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

Effect of solar radiation on photosynthesis and pigmentation in the cyanobacterium microcoleus chtihonoplastes

International Nuclear Information System (INIS)

Annan, J.N.; Galyuon, I. K. A.; Donkor, V.A.

2007-01-01

The effects of solar radiation on the photosynthetic oxygen production and pigmentation were investigated in the marine filamentous cyanobacterium. Microcoleus chthonoplastes harvested from the intertidal zone of the Biriwa coast in Ghana. The organism was exposed to unfiltered solar radiation (UV-B. UV-A and PAR) and solar radiation filtered through optical filters. WG320 (UV-A and PAR), GG400 (PAR only), and UG5 (only UV-B and UV-A), Photosynthetic oxygen production was impaired. The reduction in the rate of photosynthetic oxygen production took over 2 hours to occur. The photoinhibition due to unfiltered solar radiation and combined UV-A and PAR were most severe. Absorption spectra of the crude extracts of M. chthonoplastes, indicated the presence of chlorophyll a, carotenoids, phycoerythrin and phycocyanin as the photosynthetic pigments, which were significantly bleached under the various solar radiation wavelengths. Generally, the phycobilins were affected most. Fluorescence measurements showed peaks that decreased significantly in amplitude and also underwent a shift towards shorter wavelengths, with prolonged exposure time, indicating that energy transfer from the accessory pigments was adversely affected. The implication is that increased solar radiation may have severe consequences on the marine ecosystem. (au)

Degradation in perovskite solar cells stored under different environmental conditions

Science.gov (United States)

Chauhan, Abhishek K.; Kumar, Pankaj

2017-08-01

Investigations carried out on the degradation of perovskite solar cells (PSCs) stored in different open air environmental conditions are reported here. The solar cells were stored in the open in the dark inside the laboratory (relative humidity 47  ±  5%, temperature 23  ±  4 °C), under compact fluorescent lamp (CFL) illumination (irradiance 10 mW cm2, relative humidity 47  ±  5%, temperature 23  ±  4 °C) and under natural sunlight outside the laboratory. In the outdoor storage situation the surrounding conditions varied from time to time and the environmental conditions during the day (irradiance 100 mW/cm2, relative humidity ~18%, temperature ~45 °C at noon) were entirely different from those at night (irradiance 0 mW/cm2, relative humidity ~66%, temperature ~16 °C at midnight). The photovoltaic parameters were measured from time to time inside the laboratory as per the International Summit on Organic Photovoltaic Stability (ISOS) protocols. All the photovoltaic parameters, such as short circuit current density (J sc), open circuit voltage (V oc), fill factor (FF) and power conversion efficiency (PCE), of the solar cells stored outdoors decayed more rapidly than those stored under CFL or in the dark. The solar cells stored in the dark exhibited maximum stability. While the encapsulated solar cells stored outdoors were completely dead after about 560 h, the solar cells stored under CFL illumination retained  >60% of their initial efficiency even after 1100 h. However, the solar cells stored in the dark and tested up to ~1100 h did not show any degradation in PCE but on the contrary exhibited slight improvement, and this improvement was mainly because of improvement in their V oc. Rapid degradation in the open air outside the laboratory under direct sunlight compared with the dark and CFL storage has been attributed to high temperature during the day, high humidity at night, high solar illumination intensity and the

The development of an Infrared Environmental System for TOPEX Solar Panel Testing

Science.gov (United States)

Noller, E.

1994-01-01

Environmental testing and flight qualification of the TOPEX/POSEIDON spacecraft solar panels were performed with infrared (IR) lamps and a control system that were newly designed and integrated. The basic goal was more rigorous testing of the costly panels' new composite-structure design without jeopardizing their safety. The technique greatly reduces the costs and high risks of testing flight solar panels.

8 years of Solar Spectral Irradiance Observations from the ISS with the SOLAR/SOLSPEC Instrument

Science.gov (United States)

Damé, L.; Bolsée, D.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Bekki, S.; Pereira, N.; Cessateur, G.; Marchand, M.; Thiéblemont, R.; Foujols, T.

2016-12-01

Accurate measurements of Solar Spectral Irradiance (SSI) are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry). The acquisition of a top of atmosphere reference solar spectrum and of its temporal and spectral variability during the unusual solar cycle 24 is of prime interest for these studies. These measurements are performed since April 2008 with the SOLSPEC spectro-radiometer from the far ultraviolet to the infrared (166 nm to 3088 nm). This instrument, developed under a fruitful LATMOS/BIRA-IASB collaboration, is part of the Solar Monitoring Observatory (SOLAR) payload, externally mounted on the Columbus module of the International Space Station (ISS). The SOLAR mission, with its actual 8 years duration, will cover almost the entire solar cycle 24. We present here the in-flight operations and performances of the SOLSPEC instrument, including the engineering corrections, calibrations and improved know-how procedure for aging corrections. Accordingly, a SSI reference spectrum from the UV to the NIR will be presented, together with its UV variability, as measured by SOLAR/SOLSPEC. Uncertainties on these measurements and comparisons with other instruments will be briefly discussed.

76 FR 70125 - Notice of Availability of the Draft Environmental Impact Statement for the Proposed Solar Reserve...

Science.gov (United States)

2011-11-10

... Environmental Impact Statement for the Proposed Solar Reserve LLC Quartzsite Solar Energy Project, La Paz County... (DEIS) for the proposed Quartzsite Solar Energy Project (Project), in La Paz County, Arizona, and the... http://www.blm.gov/az/st/en/prog/energy/solar/quartzsite_solar_energy.html . Copies of the document are...

Elevated level of polysaccharides in a high level UV-B tolerant cell ...

African Journals Online (AJOL)

Jane

2011-04-26

Apr 26, 2011 ... A cell line of Bupleurum scorzonerifolium Willd with high level ... mechanisms to repair UV-induced damages via repairing ... for treatment or prevention of solar radiation. ..... working as both UV-B absorbing compounds and.

Solar Environmental Disturbances

Science.gov (United States)

2007-11-02

Astronomische Nachrichten 324, 303-304: Design and Development of the Advanced Technology Solar Telescope Keller, C.U., Rimmele, T.R., Hill, F...Keil, S.L., Oschmann, J.M., and the ATST Team 2002, Astronomische Nachrichten 323, 294-298: The Advanced Technology Solar Telescope Mozer, J.B

Environmental occurrence and ecological risk assessment of organic UV filters in marine organisms from Hong Kong coastal waters.

Science.gov (United States)

Sang, Ziye; Leung, Kelvin Sze-Yin

2016-10-01

Organic UV filters, now considered to be emerging contaminants in aquatic ecosystems, are being intensively tracked in environmental waters worldwide. However, their environmental fate and impact of these contaminants on marine organisms remains largely unknown, especially in Asia. This work elucidates the occurrence and the ecological risks of seven UV filters detected in farmed fish, wild mussels and some other wild organisms collected from local mariculture farms in Hong Kong. For all of the organisms, ethylhexyl methoxycinnamate (EHMC) and octyl dimethyl p-aminobenzoic acid (OD-PABA) were the predominant contaminants with the highest concentrations up to 51.3 and 24.1ng/g (dw), respectively; lower levels were found for benzophenone-8 (BP-8), octocrylene (OC) and benzophenone-3 (BP-3) from UV filters indicated a positive correlation between their measured concentrations and the anthropogenic activities responsible for their direct emission. The ecological risk assessment specific to the marine aquatic environment was carried out. The risk quotient (RQ) values of EHMC and BP-3 were calculated as 3.29 and 2.60, respectively, indicating these two UV filters may pose significant risks to the marine aquatic environment. Copyright © 2016 Elsevier B.V. All rights reserved.

The influence of urban area opacity on biologically active UV-B irradiance

Science.gov (United States)

Chubarova, Nataly; Rozental', Victor

2013-04-01

The study of UV irradiance changes in urban area is an essential problem due to the significant effect of UV irradiance on human health which can be positive (vitamin D synthesis) and negative (erythema, skin cancer, eye damage). According to the results of several experiments within the Moscow megacity we studied the effects of urban area opacity on the different types of biologically active UV-B irradiance on the base of a specially developed mobile photometric complex snd additional measurements of the urban opacity by Nikon Fisheye Converter FC-E8. We analyzed both the level of erythemally-active irradiance and the UV eye damaging radiation using the broadband UVB-1 YES pyranometer calibrated against ultraviolet spectroradiometer Bentham DTM-300 of the Medical University of Innsbruck (courtesy of Dr. M.Blumthaler). In order to estimate the effects of the urban opacity the measurements were normalized on similar measurements at the Meteorological Observatory of Moscow State University with zero opacity. This ratio is defined as an urban radiative transmittance (URT). Different atmospheric conditions were considered. In cloudy conditions the effect of opacity on URT is much less than that in conditions when the sun disk is open from clouds. We revealed some spectral features in transmittance of biologically active UV-B irradiance which is characterized by higher URT variations in overcast cloudy conditions due to more intensive scattering and smaller direct solar radiation component. In the absence of cloudiness the effect of opacity was studied for open and screening solar disk conditions. We obtained much higher URT in UVB spectral region compared with that for total solar irradiance for screening solar disk conditions with a significant URT dependence on the opacity only in UVB spectral region. No URT dependence was obtained for total solar irradiance in these conditions. Some model calculations were fulfilled to match the experimental results.

Cross-calibration of far UV spectra of solar system objects and the heliosphere

CERN Document Server

Snow, Martin; Bonnet, Roger-Maurice

2013-01-01

This book is the result of a working group sponsored by ISSI in Bern, which was initially created to study possible ways to calibrate a Far Ultraviolet (FUV) instrument after launch. In most cases, ultraviolet instruments are well calibrated on the ground, but unfortunately, optics and detectors in the FUV are very sensitive to contaminants and it is very challenging to prevent contamination before and during the test and launch sequences of a space mission. Therefore, ground calibrations need to be confirmed after launch and it is necessary to keep track of the temporal evolution of the sensitivity of the instrument during the mission. The studies presented here cover various fields of FUV spectroscopy with the exclusion of direct solar UV spectroscopy, including a catalog of stellar spectra, data-sets of lunar Irradiance, observations of comets and measurements of the interplanetary background. Detailed modeling of the interplanetary background is presented as well. This work also includes comparisons of ol...

UV and solar photo-degradation of naproxen: TiO₂ catalyst effect, reaction kinetics, products identification and toxicity assessment.

Science.gov (United States)

Jallouli, Nabil; Elghniji, Kais; Hentati, Olfa; Ribeiro, Ana R; Silva, Adrián M T; Ksibi, Mohamed

2016-03-05

Direct photolysis and TiO2-photocatalytic degradation of naproxen (NPX) in aqueous solution were studied using a UV lamp and solar irradiation. The degradation of NPX was found to be in accordance with pseudo-first order kinetics, the photocatalytic process being more efficient than photolysis. The NPX removal by photolysis (pHinitial 6.5) was 83% after 3h, with 11% of chemical oxygen demand (COD) reduction, whereas the TiO2-UV process led to higher removals of both NPX (98%) and COD (25%). The apparent pseudo-first-order rate constant (kapp) for NPX degradation by photolysis ranged from 0.0050 min(-1) at pH 3.5 to 0.0095 min(-1) at pH 6.5, while it was estimated to be 0.0063 min(-1) under acidic conditions in photocatalysis, increasing by 4-fold at pH 6.5. Ultra High Performance Liquid chromatography (UHPLC) coupled with a triple quadrupole detector and also a hybrid mass spectrometer which combines the linear ion trap triple quadrupole (LTQ) and OrbiTrap mass analyser, were used to identify NPX degradation products. The main intermediates detected were 1-(6-methoxynaphtalene-2-yl) ethylhydroperoxide, 2-ethyl-6-methoxynaphthalene, 1-(6-methoxynaphtalen-2-yl) ethanol, 1-(6-methoxynaphtalen-2-yl) ethanone and malic acid. Solar photocatalysis of NPX showed COD removals of 33% and 65% after 3 and 4h of treatment, respectively, and some reduction of acute toxicity, evaluated by the exposure of Eisenia andrei to OECD soils spiked with NPX-treated solutions. Copyright © 2015 Elsevier B.V. All rights reserved.

Exploring the Inner Acceleration Region of Solar Wind: A Study Based on Coronagraphic UV and Visible Light Data

Science.gov (United States)

Bemporad, A.

2017-09-01

This work combined coronagraphic visible light (VL) and UV data to provide with an unprecedented view of the inner corona where the nascent solar wind is accelerated. The UV (H I Lyα) and VL (polarized brightness) images (reconstructed with SOHO/UVCS, LASCO, and Mauna Loa data) have been analyzed with the Doppler dimming technique to provide for the first time daily 2D images of the radial wind speed between 1 and 6 R ⊙ over 1 month of observations. Results show that both polar and equatorial regions are characterized at the base of the corona by plasma outflows at speeds > 100 km s-1. The plasma is then decelerated within ˜1.5 R ⊙ at the poles and ˜2.0 R ⊙ at the equator, where local minima of the expansion speeds are reached, and gently reaccelerated higher up, reaching speeds typical of fast and slow wind components. The mass flux is highly variable with latitude and time at the equator and more uniform and stable over the poles. The polar flow is asymmetric, with speeds above the south pole lower than those above the north pole. A correlation (anticorrelation) between the wind speed and its density is found below (above) ˜1.8 R ⊙. The 2D distribution of forces responsible for deceleration and reacceleration of solar wind is provided and interpreted in terms of Alfvén waves. These results provide a possible connection between small-scale outflows reported with other instruments at the base of the corona and bulk wind flows measured higher up.

Tertiary treatment of pulp mill wastewater by solar photo-Fenton

International Nuclear Information System (INIS)

Lucas, Marco S.; Peres, José A.; Amor, Carlos; Prieto-Rodríguez, Lucía; Maldonado, Manuel I.; Malato, Sixto

2012-01-01

Highlights: ► We firstly report a real pulp mill wastewater treatment by solar photo-Fenton in a CPC reactor. Fenton reagent experiments were tested firstly. ► Solar photo-Fenton presents excellent ability to treat the pulp mill wastewater. ► Experimental conditions were optimised. ► Biodegradability and toxicity tests (respirometry assays and BOD 5 /COD ratio) were performed during the wastewater treatment. ► A way to reduce the economic and environmental impact was evaluated. - Abstract: This work reports on pulp mill wastewater (PMW) tertiary treatment by Fenton (Fe 2+ /H 2 O 2 ) and solar photo-Fenton (Fe 2+ /H 2 O 2 /UV) processes in a pilot plant based on compound parabolic collectors (CPCs). Solar photo-Fenton reaction is much more efficient than the respective dark reaction under identical experimental conditions. It leads to DOC mineralisation, COD and total polyphenols (TP) removal higher than 90%. The solar photo-Fenton experiment with 5 mg Fe L −1 reaches 90% of DOC mineralisation with 31 kJ L −1 of UV energy and 50 mM of H 2 O 2 . The initial non-biodegradability of PMW, as shown by respirometry assays and BOD 5 /COD ratio, can be changed after a solar photo-Fenton treatment. Experiments with 20 and 50 mg Fe L −1 revealed that solar photo-Fenton can reach the same DOC degradation (90%), however, consuming less H 2 O 2 and time. Diluting the initial organic load to 50% also diminishes the dosage of H 2 O 2 and the necessary reaction time to achieve high DOC removals. Accordingly, solar photo-Fenton can be considered an alternative or complementary process to improve the performance of a biologic treatment and, subsequently, achieve legal limits on discharge into natural waters.

Effect of pentacene/Ag anode buffer and UV-ozone treatment on durability of small-molecule organic solar cells

International Nuclear Information System (INIS)

Inagaki, S; Sueoka, S; Harafuji, K

2017-01-01

Three surface modifications of indium tin oxide (ITO) are experimentally investigated to improve the performance of small-molecule organic solar cells (OSCs) with an ITO/anode buffer layer (ABL)/copper phthalocyanine (CuPc)/fullerene/bathocuproine/Ag structure. An ultrathin Ag ABL and ultraviolet (UV)-ozone treatment of ITO independently improve the durability of OSCs against illumination stress. The thin pentacene ABL provides good ohmic contact between the ITO and the CuPc layer, thereby producing a large short-circuit current. The combined use of the abovementioned three modifications collectively achieves both better initial performance and durability against illumination stress. (paper)

Effect of pentacene/Ag anode buffer and UV-ozone treatment on durability of small-molecule organic solar cells

Science.gov (United States)

Inagaki, S.; Sueoka, S.; Harafuji, K.

2017-06-01

Three surface modifications of indium tin oxide (ITO) are experimentally investigated to improve the performance of small-molecule organic solar cells (OSCs) with an ITO/anode buffer layer (ABL)/copper phthalocyanine (CuPc)/fullerene/bathocuproine/Ag structure. An ultrathin Ag ABL and ultraviolet (UV)-ozone treatment of ITO independently improve the durability of OSCs against illumination stress. The thin pentacene ABL provides good ohmic contact between the ITO and the CuPc layer, thereby producing a large short-circuit current. The combined use of the abovementioned three modifications collectively achieves both better initial performance and durability against illumination stress.

Environment Canada's Children's UV Index Sun Awareness Programme

International Nuclear Information System (INIS)

Fergusson, A.

2000-01-01

In 1992, Canada introduced the UV Index forecast programme to increase public awareness of UV radiation, to support health agencies in educating the public about UV risks, and to assist individuals in making healthy lifestyle decisions. A national sun health survey in 1997 indicated that about half of adults reported taking extra precautions to protect themselves from the sun on days when the UV Index was rated 'high'. In response to this concern in 1998, Environment Canada produced an UN Index poster that was sent to 3000 elementary schools across Canada. The poster targeted children between the ages of 8 and 15 and provided information to minimise the risk to their health from solar UV radiation without spoiling their outdoor fun. Based on this experience Environment Canada produced in 1999, the Daily UV Index and Calendar Poster that was sent to 14,000 elementary schools across Canada. An UV Index website has been created to provide information to students and teachers on the science of UV radiation and the UV Index. (author)

Energy, economic and environmental analysis of metal oxides nanofluid for flat-plate solar collector

International Nuclear Information System (INIS)

Faizal, M.; Saidur, R.; Mekhilef, S.; Alim, M.A.

2013-01-01

Highlights: • By using nanofluid, smaller and compact solar collector can be produced. • The average value of 220 MJ embodied energy can be saved. • The payback period of using nanofluid solar collector is around 2.4 years. • Around 170 kg less CO 2 emissions in average for nanofluid solar collector. • Environmental damage cost is lower with the nanofluid based solar collector. - Abstract: For a solar thermal system, increasing the heat transfer area can increase the output temperature of the system. However, this approach leads to a bigger and bulkier collector. It will then increase the cost and energy needed to manufacture the solar collector. This study is carried out to estimate the potential to design a smaller solar collector that can produce the same desired output temperature. This is possible by using nanofluid as working fluid. By using numerical methods and data from literatures, efficiency, size reduction, cost and embodied energy savings are calculated for various nanofluids. From the study, it was estimated that 10,239 kg, 8625 kg, 8857 kg and 8618 kg total weight for 1000 units of solar collectors can be saved for CuO, SiO 2 , TiO 2 and Al 2 O 3 nanofluid respectively. The average value of 220 MJ embodied energy can be saved for each collector, 2.4 years payback period can be achieved and around 170 kg less CO 2 emissions in average can be offset for the nanofluid based solar collector compared to a conventional solar collector. Finally, the environmental damage cost can also be reduced with the nanofluid based solar collector

Cu-doped TiO2 nanoparticles enhance survival of Shewanella oneidensis MR-1 under Ultraviolet Light (UV) exposure

International Nuclear Information System (INIS)

Wu, Bing; Zhuang, Wei-Qin; Sahu, Manoranjan; Biswas, Pratim; Tang, Yinjie J.

2011-01-01

It has been shown that photocatalytic TiO 2 nanoparticles (NPs) can be used as an efficient anti-microbial agent under UV light due to generation of reactive oxygen species (ROS), while Shewanella oneidensis MR-1 is a metal-reducing bacterium highly susceptible to UV radiation. Interestingly, we found that the presence of Cu-doped TiO 2 NPs in the cultural medium dramatically increased the survival rates (based on colony-forming unit) of strain MR-1 by over 10,000-fold (incubation without shaking) and ∼ 200 fold (incubation with shaking) after a 2-h exposure to UV light. Gene expression results (via qPCR measurement) indicated that the DNA repair gene recA in MR-1 was significantly induced by UV exposure (indicating cellular damage under UV stress), but the influence of NPs on recA expression was not statistically evident. Plausible explanations to NP attenuation of UV stresses are: 1. TiO 2 based NPs are capable of scattering and absorbing UV light and thus create a shading effect to protect MR-1 from UV radiation; 2. more importantly, Cu-doped TiO 2 NPs can co-agglomerate with MR-1 to form large flocs that improves cells' survival against the environmental stresses. This study improves our understanding of NP ecological impacts under natural solar radiation and provides useful insights to application of photocatalytic-NPs for bacterial disinfection.

The Daidzein Metabolite, 6,7,4'-Trihydroxyisoflavone, Is a Novel Inhibitor of PKCα in Suppressing Solar UV-Induced Matrix Metalloproteinase 1

Directory of Open Access Journals (Sweden)

Tae-Gyu Lim

2014-11-01

Full Text Available Soy isoflavone is an attractive source of functional cosmetic materials with anti-wrinkle, whitening and skin hydration effects. After consumption, the majority of soy isoflavones are converted to their metabolites in the human gastrointestinal tract. To understand the physiological impact of soy isoflavone on the human body, it is necessary to evaluate and address the biological function of its metabolites. In this study, we investigated the effect of 6,7,4'-trihydroxyisoflavone (6,7,4'-THIF, a major metabolite of daidzein, against solar UV (sUV-induced matrix metalloproteinases (MMPs in normal human dermal fibroblasts. MMPs play a critical role in the degradation of collagen in skin, thereby accelerating the aging process of skin. The mitogen-activated protein/extracellular signal-regulated kinase (MEK/extracellular signal-regulated kinase (ERK, mitogen-activated protein kinase (MKK3/6/p38 and MKK4/c-Jun N-terminal kinases (JNK signaling pathways are known to modulate MMP-1 function, and their activation by sUV was significantly reduced by 6,7,4'-THIF pretreatment. Our results also indicated that the enzyme activity of protein kinase C (PKCα, an upstream regulator of MKKs signaling, is suppressed by 6,7,4'-THIF using the in vitro kinase assay. Furthermore, the direct interaction between 6,7,4'-THIF and endogenous PKCα was confirmed using the pull-down assay. Not only sUV-induced MMP-1 expression, but also sUV-induced signaling pathway activation were decreased in PKCα knockdown cells. Overall, we elucidated the inhibitory effect of 6,7,4'-THIF on sUV-induced MMPs and suggest PKCα as its direct molecular target.

Reproductive, morphological, and phytochemical responses of Arabidopsis thaliana ecotypes to enhanced UV-B radiation

Energy Technology Data Exchange (ETDEWEB)

Trumbull, V.L.; McCloud, E.S.; Paige, K.N. (Univ. of Illinois, Urbana, IL (United States))

1994-06-01

Two ecotypes of Arabidopsis thaliana, collected from Libya and Norway, were grown in the greenhouse under. UV-B doses of 0 and 10.5 kJ m[sup [minus]2] UV-B[sub BE]. The high UV-B dose simulated midsummer ambient conditions over Libya and a 40% reduction in stratospheric ozone over Norway. The Libyan ectotype, which originated from latitudes where solar UV-B is high, showed no UV-B induced damage to plant growth. However the Norwegian ecotype, which originated from latitudes where solar UV-B is low, showed a significant reduction in plant height, inflorescence weight, and rosette weight in response to enhanced UV-B. Although fruit and seed number for both ecotypes were unaffected by enhanced UV-B radiation the germination success of the seeds harvested from the irradiated Norwegian plants were significantly reduced. The two ecotypes also differed with respect to their accumulation of kaempferol, a putative UV-B protective filter. The Libyan ecotype increased kaempferol concentration by 38% over the 0 kJ treatment whereas the Norwegian ecotype increased by only 15%. These data suggest that, for these ecotypes, variation in UV-B sensitivity may be explained by the differential induction of UV-absorbing leaf pigments.

Beneficial and Detrimental Effects of UV on Aquatic Organisms: Implications of Spectral Variation

NARCIS (Netherlands)

Williamson, C.E.; Neale, P.J.; Grad, G.; Lange, de H.J.; Hargreaves, B.R.

2001-01-01

Solar ultraviolet radiation (UVR) may have beneficial as well as detrimental effects on living systems. For example, UV-B radiation (280¿320 nm) is generally damaging, while UV-A radiation (320¿400 nm) may cause damage or stimulate beneficial photorepair of UV-B damage. The nature of both direct and

Detection of UV Pulse from Insulators and Application in Estimating the Conditions of Insulators

Science.gov (United States)

Wang, Jingang; Chong, Junlong; Yang, Jie

2014-10-01

Solar radiation in the band of 240-280 nm is absorbed by the ozone layer in the atmosphere, and corona discharges from high-voltage apparatus emit in air mainly in the 230-405 nm range of ultraviolet (UV), so the band of 240-280 nm is called UV Solar Blind Band. When the insulators in a string deteriorate or are contaminated, the voltage distribution along the string will change, which causes the electric fields in the vicinity of insulators change and corona discharge intensifies. An UV pulse detection method to check the conditions of insulators is presented based on detecting the UV pulse among the corona discharge, then it can be confirmed that whether there exist faulty insulators and whether the surface contamination of insulators is severe for the safe operation of power systems. An UV-I Insulator Detector has been developed, and both laboratory tests and field tests have been carried out which demonstrates the practical viability of UV-I Insulator Detector for online monitoring.

A new UV-A/B protecting pigment in the terrestrial cyanobacterium Nostoc commune

International Nuclear Information System (INIS)

Scherer, S.; Chen, T.W.; Boeger, P.

1988-01-01

A new ultraviolet (UV)-A/B absorbing pigment with maxima at 312 and 330 nanometers from the cosmopolitan terrestrial cyanobacterium Nostoc commune is described. The pigment is found in high amounts (up to 10% of dry weight) in colonies grown under solar UV radiation but only in low concentrations in laboratory cultures illuminated by artificial light without UV. Its experimental induction by UV as well as its capacity to efficiently protect Nostoc against UV radiation is reported

76 FR 47608 - Notice of Availability of the Final Environmental Impact Statement for the Rice Solar Energy, LLC...

Science.gov (United States)

2011-08-05

... Availability of the Final Environmental Impact Statement for the Rice Solar Energy, LLC Rice Solar Energy... Desert Conservation Area (CDCA) Plan Amendment for the Rice Solar Energy Project (RSEP) in Riverside... proposed Rice Solar Energy Project (Project) is a 150 megawatt (MW) solar electric power plant that would...

Effects of simulated solar UVB radiation on early developmental stages of the northwestern salamander (Ambystoma gracile) from three lakes

Science.gov (United States)

Calfee, R.D.; Little, E.E.; Pearl, C.A.; Hoffman, R.L.

2010-01-01

Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290-320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66 of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation. Copyright 2010 Society for the Study of Amphibians and Reptiles.

UV and solar photo-degradation of naproxen: TiO_2 catalyst effect, reaction kinetics, products identification and toxicity assessment

International Nuclear Information System (INIS)

Jallouli, Nabil; Elghniji, Kais; Hentati, Olfa; Ribeiro, Ana R.; Silva, Adrián M.T.; Ksibi, Mohamed

2016-01-01

Highlights: • Degradation kinetics and mineralization rate of naproxen (NPX) were studied. • Direct photolysis and TiO_2/UV approaches were evaluated. • The formation of by-products was followed by UHPLC-DAD-MS. • Ecological risk assessment of NPX-treated solutions was assessed using E. andrei. - Abstract: Direct photolysis and TiO_2-photocatalytic degradation of naproxen (NPX) in aqueous solution were studied using a UV lamp and solar irradiation. The degradation of NPX was found to be in accordance with pseudo-first order kinetics, the photocatalytic process being more efficient than photolysis. The NPX removal by photolysis (pH_i_n_i_t_i_a_l 6.5) was 83% after 3 h, with 11% of chemical oxygen demand (COD) reduction, whereas the TiO_2-UV process led to higher removals of both NPX (98%) and COD (25%). The apparent pseudo-first-order rate constant (k_a_p_p) for NPX degradation by photolysis ranged from 0.0050 min"−"1 at pH 3.5 to 0.0095 min"−"1 at pH 6.5, while it was estimated to be 0.0063 min"−"1 under acidic conditions in photocatalysis, increasing by 4-fold at pH 6.5. Ultra High Performance Liquid chromatography (UHPLC) coupled with a triple quadrupole detector and also a hybrid mass spectrometer which combines the linear ion trap triple quadrupole (LTQ) and OrbiTrap mass analyser, were used to identify NPX degradation products. The main intermediates detected were 1-(6-methoxynaphtalene-2-yl) ethylhydroperoxide, 2-ethyl-6-methoxynaphthalene, 1-(6-methoxynaphtalen-2-yl) ethanol, 1-(6-methoxynaphtalen-2-yl) ethanone and malic acid. Solar photocatalysis of NPX showed COD removals of 33% and 65% after 3 and 4 h of treatment, respectively, and some reduction of acute toxicity, evaluated by the exposure of Eisenia andrei to OECD soils spiked with NPX-treated solutions.

Hybrid UV-Ozone-Treated rGO-PEDOT:PSS as an Efficient Hole Transport Material in Inverted Planar Perovskite Solar Cells

Science.gov (United States)

Wang, Shuying; Huang, Xiaona; Sun, Haoxuan; Wu, Chunyang

2017-12-01

Inverted planar perovskite solar cells (PSCs), which are regarded as promising devices for new generation of photovoltaic systems, show many advantages, such as low-temperature film formation, low-cost fabrication, and smaller hysteresis compared with those of traditional n-i-p PSCs. As an important carrier transport layer in PSCs, the hole transport layer (HTL) considerably affects the device performance. Therefore, HTL modification becomes one of the most critical issues in improving the performance of PSCs. In this paper, we report an effective and environmentally friendly UV-ozone treatment method to enhance the hydrophilia of reduced graphene oxide (rGO) with its excellent electrical performance. The treated rGO was applied to doped poly(3,4-ethylenedioxythiophene) poly(styrene-sulfonate) (PEDOT:PSS) as HTL material of PSCs. Consequently, the performance of rGO/PEDOT:PSS-doped PSCs was improved significantly, with power conversion efficiency (PCE) of 10.7%, Jsc of 16.75 mA/cm2, Voc of 0.87 V, and FF of 75%. The PCE of this doped PSCs was 27% higher than that of the PSCs with pristine PEDOT:PSS as HTL. This performance was attributed to the excellent surface morphology and optimized hole mobility of the solution-processable rGO-modified PEDOT:PSS.

The Nrf2-inducers tanshinone I and dihydrotanshinone protect human skin cells and reconstructed human skin against solar simulated UV☆

Science.gov (United States)

Tao, Shasha; Justiniano, Rebecca; Zhang, Donna D.; Wondrak, Georg T.

2013-01-01

Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photocarcinogenesis and photoaging, and an urgent need exists for improved strategies for skin photoprotection. The redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2), a master regulator of the cellular antioxidant defense against environmental electrophilic insult, has recently emerged as an important determinant of cutaneous damage from solar UV, and the concept of pharmacological activation of Nrf2 has attracted considerable attention as a novel approach to skin photoprotection. In this study, we examined feasibility of using tanshinones, a novel class of phenanthrenequinone-based cytoprotective Nrf2 inducers derived from the medicinal plant Salvia miltiorrhiza, for protection of cultured human skin cells and reconstructed human skin against solar simulated UV. Using a dual luciferase reporter assay in human Hs27 dermal fibroblasts pronounced transcriptional activation of Nrf2 by four major tanshinones [tanshinone I (T-I), dihydrotanshinone (DHT), tanshinone IIA (T-II-A) and cryptotanshinone (CT)] was detected. In fibroblasts, the more potent tanshinones T-I and DHT caused a significant increase in Nrf2 protein half-life via blockage of ubiquitination, ultimately resulting in upregulated expression of cytoprotective Nrf2 target genes (GCLC, NQO1) with the elevation of cellular glutathione levels. Similar tanshinone-induced changes were also observed in HaCaT keratinocytes. T-I and DHT pretreatment caused significant suppression of skin cell death induced by solar simulated UV and riboflavin-sensitized UVA. Moreover, feasibility of tanshinone-based cutaneous photoprotection was tested employing a human skin reconstruct exposed to solar simulated UV (80 mJ/cm2 UVB; 1.53 J/cm2 UVA). The occurrence of markers of epidermal solar insult (cleaved procaspase 3, pycnotic nuclei, eosinophilic cytoplasm, acellular cavities) was significantly attenuated in DHT

Effects of increased solar ultraviolet radiation on biogeochemical cycles

International Nuclear Information System (INIS)

Zepp, R.G.; Callaghan, T.V.; Erickson, D.J.

1995-01-01

Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical cycles thus altering both sources and sinks of greenhouse and chemically important trace gases (e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS). In terrestrial ecosystems, increased UV-B could modify both the production and decomposition of plant matter with concomitant changes in the uptake and release of atmospherically important trace gases. Decomposition processes can be accelerated when UV-B photodegrades surface litter, or retarded when the dominant effect involves changes in the chemical composition of living tissues that reduce the biodegradability of buried litter. These changes in decomposition can affect microbial production of CO2 and other trace gases and also may affect the availability of nutrients essential for plant growth. Primary production can be reduced by enhanced UV-B, but the effect is variable between species and even cultivars of some crops. Likewise, the effects of enhanced UV-B on photoproduction of CO from plant matter is species-dependent and occurs more efficiently from dead than from living matter. Aquatic ecosystems studies in several different locations have shown that reductions in current levels of solar UV-B result in enhanced primary production, and Antarctic experiments under the ozone hole demonstrated that primary production is inhibited by enhanced UV-B. In addition to its effects on primary production, solar UV radiation can reduce bacterioplankton growth in the upper ocean with potentially important effects on marine biogeochemical cycles. Decomposition processes can be retarded when bacterial activity is suppressed by enhanced UV-B radiation or stimulated when solar UV radiation photodegrades aquatic dissolved organic matter. Photodegradation of DOM results in loss of UV absorption and formation of dissolved inorganic carbon, CO, and organic substrates that are readily mineralized or taken up by aquatic

Inter-comparison of the solar UVB, UVA and global radiation clearness and UV indices for Beer Sheva and Neve Zohar (Dead Sea), Israel

International Nuclear Information System (INIS)

Kudish, A.I.; Lyubansky, V.; Evseev, E.G.; Ianetz, A.

2005-01-01

An inter-comparison of the clearness indices for the solar UVB, UVA and global radiation for Beer Sheva and Neve Zohar (Dead Sea) are presented utilizing radiation data measured from January 1995 through December 2001 for which there is a one-to-one correspondence between the measurements, viz., any day for which a hourly value for one of the sites was missing is rejected and not included in the analysis for that particular radiation type. Beer Sheva is located ca. 65 km to the west and is approximately 700 m above Neve Zohar, which is located on the western shore of the Dead Sea. The Dead Sea is the lowest terrestrial point on the earth, approximately 400 m below mean sea level. The relative magnitudes of the global, UVB and UVA radiation intensities at the two sites can be attributed to the enhanced scattering at the Dead Sea due to the longer optical path length the solar radiation must traverse at the Dead Sea. The degree of attenuation due to scattering phenomena is inversely proportional to the wavelength raised to some power and, consequently, it is greatest for UVB and very small for global radiation. The UVB and UVA solar constants were determined from the extraterrestrial radiation values tabulated by Froehlich and Wehrli [Spectral distribution of solar irradiance from 25000 nm to 250nm, in: M. Iqbal, An introduction to solar radiation, Academic Press, New York, 1981, Appendix C, pp. 380-381]. The clearness indices for global and UVA radiation were of similar magnitude, whereas those for UVB radiation were of two orders of magnitude smaller. In addition, the monthly average hourly UV Index at both sites has also been determined and an inter-comparison of the values has been performed for all available hourly values from January 1995 through August 2002 for both sites. It is observed that the monthly average hourly UV Index values at the Dead Sea are never in the extreme range

Biological responses to current UV-B radiation in Arctic regions

DEFF Research Database (Denmark)

Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

2008-01-01

on high-arctic vegetation. They supplement previous investigations from the Arctic focussing on other variables like growth etc., which have reported no or minor plant responses to UV-B, and clearly indicates that UV-B radiation is an important factor affecting plant life at high-arctic Zackenberg......Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high......-arctic regions, manipulation experiments with various set-ups have been performed. Activation of plant defence mechanisms by production of UV-B absorbing compounds was significant in ambient UV-B in comparison to a filter treatment reducing the UV-B radiation. Despite the UV-B screening response, ambient UV...

Biological responses to current UV-B radiation in Arctic regions

DEFF Research Database (Denmark)

Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

2008-01-01

Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high......-arctic regions, manipulation experiments with various set-ups have been performed. Activation of plant defence mechanisms by production of UV-B absorbing compounds was significant in ambient UV-B in comparison to a filter treatment reducing the UV-B radiation. Despite the UV-B screening response, ambient UV...... (mycorrhiza) or in the biomass of microbes in the soil of the root zone. However, the composition of the soil microbial community was different in the soils under ambient and reduced UV radiation after three treatment years. These results provide new insight into the negative impact of current UV-B fluxes...

Chronic effects of UV on human skin

International Nuclear Information System (INIS)

Cesarini, J.P.

1996-01-01

Chronic exposures and acute accidents of the skin to UV has been recognized as an important risk for skin cancers in human. Attempts have been made with mathematical models to correlate the ambient UV dose and occupational irradiations with the risk of skin cancers. Development of accurate global measurements of solar irradiance and personal dosimetry is expected in the future in order to reduce the exposure of the general population, to precise the measures to be taken for indoor and outdoor workers. (author)

Regional variations in the health, environmental, and climate benefits of wind and solar generation

OpenAIRE

Siler-Evans, Kyle; Azevedo, Inês Lima; Morgan, M. Granger; Apt, Jay

2013-01-01

When wind or solar energy displace conventional generation, the reduction in emissions varies dramatically across the United States. Although the Southwest has the greatest solar resource, a solar panel in New Jersey displaces significantly more sulfur dioxide, nitrogen oxides, and particulate matter than a panel in Arizona, resulting in 15 times more health and environmental benefits. A wind turbine in West Virginia displaces twice as much carbon dioxide as the same turbine in California. De...

Identification and assessment of environmental benefits from solar hot water production

International Nuclear Information System (INIS)

Haralambopoulos, D.; Spilanis, I.

1997-01-01

The environmental benefits associated with the utilization of solar energy for hot water production are estimated in this work. The case of a particular country, Greece, and its electricity production system is employed to show the direct consequences of substituting electricity with solar energy for hot water production. The amount of conventional fuel saved, i.e. lignite and oil, is estimated, and the reduction in air pollution is calculated. This allows the calculation of reduction emission factors for solar hot water production to be undertaken. Data, with respect to the materials and the amount of energy necessary for the construction of the solar heaters, are also presented. These can serve as inputs to an energy-environment policy framework in order to lead to reduction of air pollutants like SO 2 , NO X and particulates, and the release of the greenhouse gas CO 2 into the atmosphere. (Author)

Solar cycle variations in mesospheric carbon monoxide

Science.gov (United States)

Lee, Jae N.; Wu, Dong L.; Ruzmaikin, Alexander; Fontenla, Juan

2018-05-01

As an extension of Lee et al. (2013), solar cycle variation of carbon monoxide (CO) is analyzed with MLS observation, which covers more than thirteen years (2004-2017) including maximum of solar cycle 24. Being produced primarily by the carbon dioxide (CO2) photolysis in the lower thermosphere, the variations of the mesospheric CO concentration are largely driven by the solar cycle modulated ultraviolet (UV) variation. This solar signal extends down to the lower altitudes by the dynamical descent in the winter polar vortex, showing a time lag that is consistent with the average descent velocity. To characterize a global distribution of the solar impact, MLS CO is correlated with the SORCE measured total solar irradiance (TSI) and UV. As high as 0.8 in most of the polar mesosphere, the linear correlation coefficients between CO and UV/TSI are more robust than those found in the previous work. The photochemical contribution explains most (68%) of the total variance of CO while the dynamical contribution accounts for 21% of the total variance at upper mesosphere. The photochemistry driven CO anomaly signal is extended in the tropics by vertical mixing. The solar cycle signal in CO is further examined with the Whole Atmosphere Community Climate Model (WACCM) 3.5 simulation by implementing two different modeled Spectral Solar Irradiances (SSIs): SRPM 2012 and NRLSSI. The model simulations underestimate the mean CO amount and solar cycle variations of CO, by a factor of 3, compared to those obtained from MLS observation. Different inputs of the solar spectrum have small impacts on CO variation.

A total cost perspective on use of polymeric materials in solar collectors – Importance of environmental performance on suitability

International Nuclear Information System (INIS)

Carlsson, Bo; Persson, Helena; Meir, Michaela; Rekstad, John

2014-01-01

Highlights: • A polymeric solar collector system was compared with two traditional ones. • It was found the best in terms of climatic performance per solar heat collected. • The differences in climatic cost between the systems compared however are small. • The low climatic cost makes solar heating better compared to natural gas heating. • Use of Ecoindicator 99 for environmental cost makes solar heating even better. - Abstract: To assess the suitability of solar collector systems in which polymeric materials are used versus those in which more traditional materials are used, a case study was undertaken. In this case study a solar heating system with polymeric solar collectors was compared with two equivalent but more traditional solar heating systems: one with flat plate solar collectors and one with evacuated tube solar collectors. To make the comparison, a total cost accounting approach was adopted. The life cycle assessment (LCA) results clearly indicated that the polymeric solar collector system is the best as regards climatic and environmental performance when they are expressed in terms of the IPPC 100 a indicator and the Ecoindicator 99, H/A indicator, respectively. In terms of climatic and environmental costs per amount of solar heat collected, the differences between the three kinds of collector systems were small when compared with existing energy prices. With the present tax rates, it seems unlikely that the differences in environmental and climatic costs will have any significant influence on which system is the most favoured, from a total cost point of view. In the choice between a renewable heat source and a heat source based on the use of a fossil fuel, the conclusion was that for climatic performance to be an important economic factor, the tax or trade rate of carbon dioxide emissions must be increased significantly, given the initial EU carbon dioxide emission trade rate. The rate would need to be at least of the same order of magnitude

Skin Cancer and UV Protection

Directory of Open Access Journals (Sweden)

Tarbuk Anita

2016-03-01

Full Text Available The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75% of all deaths associated with skin cancer. The primary cause of skin cancer is long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation and family genetics. It is believed that in childhood and adolescence, 80% of UV-R gets absorbed while in the remaining, 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Reducing the exposure time to sunlight, using sunscreens and protective textiles are the three ways of UV protection. Most people think that all the clothing will protect them, but it does not provide full sun screening properties. Literature sources claim that only 1/3 of the spring and summer collections tested give off proper UV protection. This is very important during the summer months, when UV index is the highest. Fabric UV protection ability highly depends on large number of factors such as type of fiber, fabric surface, construction, porosity, density, moisture content, type and concentration of dyestuff, fluorescent whitening agents, UV-B protective agents (UV absorbers, as well as nanoparticles, if applied. For all of these reasons, in the present paper, the results of UV protecting ability according to AS/NZS 4399:1996 will be discussed to show that standard clothing materials are not always adequate to prevent effect of UV-R to the human skin; and to suggest the possibilities for its improvement for this purpose enhancing light conversion and scattering. Additionally, the discrepancy in UV protection was investigated in distilled water as well as Adriatic Sea water.

Assessment and comparison of methods for solar ultraviolet radiation measurements

Energy Technology Data Exchange (ETDEWEB)

Leszczynski, K

1995-06-01

In the study, the different methods to measure the solar ultraviolet radiation are compared. The methods included are spectroradiometric, erythemally weighted broadband and multi-channel measurements. The comparison of the different methods is based on a literature review and assessments of optical characteristics of the spectroradiometer Optronic 742 of the Finnish Centre for Radiation and Nuclear Safety (STUK) and of the erythemally weighted Robertson-Berger type broadband radiometers Solar Light models 500 and 501 of the Finnish Meteorological Institute and STUK. An introduction to the sources of error in solar UV measurements, to methods for radiometric characterization of UV radiometers together with methods for error reduction are presented. Reviews on experiences from world-wide UV monitoring efforts and instrumentation as well as on the results from international UV radiometer intercomparisons are also presented. (62 refs.).

Assessment and comparison of methods for solar ultraviolet radiation measurements

International Nuclear Information System (INIS)

Leszczynski, K.

1995-06-01

In the study, the different methods to measure the solar ultraviolet radiation are compared. The methods included are spectroradiometric, erythemally weighted broadband and multi-channel measurements. The comparison of the different methods is based on a literature review and assessments of optical characteristics of the spectroradiometer Optronic 742 of the Finnish Centre for Radiation and Nuclear Safety (STUK) and of the erythemally weighted Robertson-Berger type broadband radiometers Solar Light models 500 and 501 of the Finnish Meteorological Institute and STUK. An introduction to the sources of error in solar UV measurements, to methods for radiometric characterization of UV radiometers together with methods for error reduction are presented. Reviews on experiences from world-wide UV monitoring efforts and instrumentation as well as on the results from international UV radiometer intercomparisons are also presented. (62 refs.)

The effects of simulated solar UVB radiation on early developmental stages of the Northwestern Salamander (Ambystoma gracile) from three lakes

Science.gov (United States)

Calfee, Robin D.; Little, Edward E.; Pearl, Christopher A.; Hoffman, Robert L.

2010-01-01

Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290–320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66% of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation.

Effects of UV radiation on phytoplankton

Science.gov (United States)

Smith, Raymond C.; Cullen, John J.

1995-07-01

It is now widely documented that reduced ozone will result in increased levels of ultraviolet (UV) radiation, especially UV-B (280-320nm), incident at the surface of the earth [Watson, 1988; Anderson et al., 1991; Schoeberl and Hartmann, 1991; Frederick and Alberts, 1991; WMO, 1991; Madronich, 1993; Kerr and McElroy, 1993], and there is considerable and increasing evidence that these higher levels of UV-B radiation may be detrimental to various forms of marine life in the upper layers of the ocean. With respect to aquatic ecosystems, we also know that this biologically- damaging mid-ultraviolet radiation can penetrate to ecologically- significant depths in marine and freshwater systems [Jerlov, 1950; Lenoble, 1956; Smith and Baker, 1979; Smith and Baker, 1980; Smith and Baker, 1981; Kirk et al., 1994]. This knowledge, plus the dramatic decline in stratospheric ozone over the Antarctic continent each spring, now known to be caused by anthropogenically released chemicals [Solomon, 1990; Booth et al., 1994], has resulted in increased UV-environmental research and a number of summary reports. The United Nations Environmental Program (UNEP) has provided recent updates with respect to the effects of ozone depletion on aquatic ecosystems (Hader, Worrest, Kumar in UNEP 1989, 1991, Hader, Worrest, Kumar and Smith UNEP 1994) and the Scientific Committee on Problems of the Environment (SCOPE) has provided [SCOPE, 1992] a summary of the effects of increased UV radiation on biological systems. SCOPE has also reported [SCOPE, 1993] on the effects of increased UV on the biosphere. In addition, several books have recently been published reviewing various aspects of environmental UV photobiology [Young et al., 1993], UV effects on humans, animals and plants [Tevini, 1993], the biological effects of UV radiation in Antarctica [Weiler and Penhale, 1994], and UV research in freshwater ecosystems [Williamson and Zagarese, 1994]. Several other reviews are relevant [NAS, 1984; Caldwell

Use of UV-protective windows and window films to aid in the prevention of skin cancer.

Science.gov (United States)

Edlich, Richard F; Winters, Kathryne L; Cox, Mary Jude; Becker, Daniel G; Horowitz, Jed H; Nichter, Larry S; Britt, L D; Long, William B; Edlic, Elizabeth C

2004-01-01

People are exposed to ambient solar ultraviolet (UV) radiation throughout their daily routine, intentionally and unintentionally. Cumulative and excessive exposure to UV radiation is the behavioral cause to skin cancers, skin damage, premature skin aging, and sun-related eye disorders. More than one million new cases of skin cancer were diagnosed in the United States this year. UV radiates directly and diffusely scattered by the various environmental and atmospheric conditions and has access to the skin from all directions. Because of this diffuse UV radiation, a person situated under a covering, such as the roof of a car or house, is not completely protected from the sun's rays. Because shade structures do not protect effectively against UV radiation, there have been major advances in photoprotection of glass by the development of specially designed photoprotective windows and films. It is the purpose of this collective review to highlight the photoprotective windows and films that should be incorporated into residential, commercial, and school glass windows to reduce sun exposure. Low-emittence (low-E) coatings are microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface to reduce the U-factor by suppressing radiative heat flow as well as to limit UV radiation. The exclusive Thermaflect coating uses the most advanced, double-layer soft coat technology to continue to deliver top performance for UV protection as well as prevent heat loss in the home. This product blocks 87% of UV radiation and has an Energy Star certification in all climate zones. Tints and films have been another important advance in glass photoprotection, especially in automobiles. Quality widow film products are high-tech laminates of polyester and metallized coatings bonded by distortion-free adhesives. The International Window Film Association provides members with accreditation in solar control films, safety films, and

8 years of Solar Spectral Irradiance Variability Observed from the ISS with the SOLAR/SOLSPEC Instrument

Science.gov (United States)

Damé, Luc; Bolsée, David; Meftah, Mustapha; Irbah, Abdenour; Hauchecorne, Alain; Bekki, Slimane; Pereira, Nuno; Cessateur, Marchand; Gäel; , Marion; et al.

2016-10-01

Accurate measurements of Solar Spectral Irradiance (SSI) are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry). The acquisition of a top of atmosphere reference solar spectrum and of its temporal and spectral variability during the unusual solar cycle 24 is of prime interest for these studies. These measurements are performed since April 2008 with the SOLSPEC spectro-radiometer from the far ultraviolet to the infrared (166 nm to 3088 nm). This instrument, developed under a fruitful LATMOS/BIRA-IASB collaboration, is part of the Solar Monitoring Observatory (SOLAR) payload, externally mounted on the Columbus module of the International Space Station (ISS). The SOLAR mission, with its actual 8 years duration, will cover almost the entire solar cycle 24. We present here the in-flight operations and performances of the SOLSPEC instrument, including the engineering corrections, calibrations and improved know-how procedure for aging corrections. Accordingly, a SSI reference spectrum from the UV to the NIR will be presented, together with its variability in the UV, as measured by SOLAR/SOLSPEC for 8 years. Uncertainties on these measurements and comparisons with other instruments will be briefly discussed.

Evaluating the effects of UV-B and UV-A irradiances on plant pigments, photosynthesis and growth in Glycine max L

International Nuclear Information System (INIS)

Middleton, E.H.M.

1993-01-01

Increasing penetration of UV-B radiation to the earth's surface resulting from stratospheric ozone depletion is an important environmental concern, but plant response to UV-B irradiation has been difficult to assess. The UV-A irradiance has not been specifically measured or controlled previously. The experimental UV-A was controlled in a series of three glasshouse experiments conducted under high photosynthetic photon flux (midday PPF ≥ 1200 μmol m -2 s -1 ). Low (LT) and High (HT) daily UV-B BE irradiances (10.7; 14.1 kJ m -2 ) were utilized in two experiments, whereas treatments with different UV-B BE :UV-A ratios ( BE :UV-A ratios

The SOLAR-C Mission: Plan B Payload Concept

Science.gov (United States)

Shimizu, T.; Sakao, T.; Katsukawa, Y.; Group, J. S. W.

2012-08-01

The telescope concepts for the SOLAR-C Plan B mission as of the time of the Hinode-3 meeting were briefly presented for having comments from the international solar physics community. The telescope candidates are 1) near IR-visible-UV telescope with 1.5m aperture and enhanced spectro-polarimetric capability, 2) UV/EUV high throughput spectrometer, and 3) next generation X-ray telescope.

Occurrence of UV-absorbing, mycosporine-like compounds among cyanobacterial isolates and an estimate of their screening capacity

International Nuclear Information System (INIS)

Garcia-Pichel, F.; Castenholz, R.W.

1993-01-01

Many cyanobacteria inhabit environments with intense solar radiation. Among the mechanisms to prevent UV photodamage are negative photomovements and the synthesis of UV sunscreen compounds. To assess how common and diverse UV sunscreen substances are among cyanobacteria living under intense solar radiation, the researchers analysed isolates of cyanobacteria for mycosporine amino acids (MAAs)-like, UV-absorbing, water-soluable substances. The cellular locations and the effect of UV radiation on their specific contents were also investigated. MAAs are common but diverse among terrestrial cyanobacteria, most often occuring in species with extracellular scytonemin. The spectral complementation suggests that the combined action of scytonemin and MAA may be responsible for sunscreen effects at shorter UV wavelengths, while the effect at longer wavelenths must be due solely to scytonemin. The authors conclude that these compounds have a significant effect in preventing UV radiation damage. 34 refs., 2 figs., 4 tabs

Personal solar UVR exposure studies using a new miniature electronic dosimeter/datalogger

International Nuclear Information System (INIS)

Gies, H.P.; Roy, C.R.; Toomey, S.; Borland, R.; Dixon, H.

1996-01-01

ambient UVR could provide quantitative information on whether they preferentially choose shade if available. Average relative exposures to solar UVR in comparison to ambient range from 0.05 to 0.4. However, the variations in UVR exposure rate, measured over 1 minute intervals, ranged from virtually zero to 100% of ambient, depending upon the orientation of the subject (and thus the detector) and the immediate environmental conditions such as the presence of shade or other obstructions. Information gathered in this pilot study coupled with the various difficulties experienced in data collection allowed modifications and improvements to be made to the questionnaires and the procedures before the planned full scale study commenced. A number of small design changes were also made to the UV dosimeter datalogger units to help prevent accidental erasure or loss of data. Relative exposures to solar UVR are a significant fraction of ambient radiation. Behaviour outdoors is the dominant factor affecting personal exposure to solar UVR. Subjects choosing shade where it was available had significantly lower solar UVR exposures, by a factor of 2 or more, in comparison to sun seekers

Solar ultraviolet radiation induced variations in the stratosphere and mesosphere

Science.gov (United States)

Hood, L. L.

1987-01-01

The detectability and interpretation of short-term solar UV induced responses of middle atmospheric ozone, temperature, and dynamics are reviewed. The detectability of solar UV induced perturbations in the middle atmosphere is studied in terms of seasonal and endogenic dynamical variations. The interpretation of low-latitude ozone and possible temperature responses on the solar rotation time scale is examined. The use of these data to constrain or test photochemical model predictions is discussed.

Photocatalytic Activity and Optical Properties of Blue Persistent Phosphors under UV and Solar Irradiation

Directory of Open Access Journals (Sweden)

C. R. García

2016-01-01

Full Text Available Blue phosphorescent strontium aluminosilicate powders were prepared by combustion synthesis route and a postannealing treatments at different temperatures. X-ray diffraction analysis showed that phosphors are composed of two main hexagonal phases: SrAl2O4 and Sr3Al32O51. The morphology of the phosphors changed from micrograins (1000°C to a mixture of bars and hexagons (1200°C and finally to only hexagons (1300°C as the annealing temperature is increased. Photoluminescence spectra showed a strong blue-green phosphorescent emission centered at λem=455 nm, which is associated with 4f65d1→4f6  (8S7/2 transition of the Eu2+. The sample annealed at 1200°C presents the highest luminance value (40 Cd/m2 with CIE coordinates (0.1589, 0.1972. Also, the photocatalytic degradation of methylene blue (MB under UV light (at 365 nm was monitored. Samples annealed at 1000°C and 1300°C presented the highest percentage of degradation (32% and 38.5%, resp. after 360 min. In the case of photocatalytic activity under solar irradiation, the samples annealed at 1000°C, 1150°C, and 1200°C produced total degradation of MB after only 300 min. Hence, the results obtained with solar photocatalysis suggest that our powders could be useful for water cleaning in water treatment plants.

Solar-Powered Compaction Garbage Bins in Public Areas: A Preliminary Economic and Environmental Evaluation

Directory of Open Access Journals (Sweden)

Long Duc Nghiem

2010-02-01

Full Text Available An excel-based model was developed to evaluate economic and environmental benefits of the solar-powered compaction garbage bins in public areas in Australia. Input data were collected from Brisbane and Wollongong City councils, and Sydney Olympic Park. The results demonstrate that solar-powered compaction garbage bins would provide environmental benefits in all scenarios. However, results of the economic analysis of the three studied areas varied significantly. The unique situation of Sydney Olympic Park made implementation in that facility particularly appealing. A lower monthly rental cost is needed for the implementation of this novel waste management practice.

Effects of UV-B irradiation on photomovement in the desmid, Cosmarium cucumis

International Nuclear Information System (INIS)

Haeder, D.-P.

1987-01-01

Monochromatic UV-B irradiation affects neither the absorption nor the fluorescence of the bulk pigments in the desmid Cosmarium cucumis but it impairs photomovement of these organisms at fluence rates which are not higher than the ambient level of solar UV-B irradiation. Photoaccumulations and phototaxis are strongly inhibited especially at wavelengths <= 300 nm while photodispersal at higher white light fluence rates is hardly affected by supplementary UV-B. This effect has important consequences for the growth and survival of populations in their natural environment: these photosynthetic organisms utilize photomovement to find and stay in areas of suitable visible light fluence rates. The UV-B component of solar irradiation both impairs the strategy of the organisms to find a suitable position and the escape mechanism by which the cells move out of areas with too strong white illuminances which photooxidize the bulk pigments and bleach the population within a few days. (author)

UV Reconstruction Algorithm And Diurnal Cycle Variability

Science.gov (United States)

Curylo, Aleksander; Litynska, Zenobia; Krzyscin, Janusz; Bogdanska, Barbara

2009-03-01

UV reconstruction is a method of estimation of surface UV with the use of available actinometrical and aerological measurements. UV reconstruction is necessary for the study of long-term UV change. A typical series of UV measurements is not longer than 15 years, which is too short for trend estimation. The essential problem in the reconstruction algorithm is the good parameterization of clouds. In our previous algorithm we used an empirical relation between Cloud Modification Factor (CMF) in global radiation and CMF in UV. The CMF is defined as the ratio between measured and modelled irradiances. Clear sky irradiance was calculated with a solar radiative transfer model. In the proposed algorithm, the time variability of global radiation during the diurnal cycle is used as an additional source of information. For elaborating an improved reconstruction algorithm relevant data from Legionowo [52.4 N, 21.0 E, 96 m a.s.l], Poland were collected with the following instruments: NILU-UV multi channel radiometer, Kipp&Zonen pyranometer, radiosonde profiles of ozone, humidity and temperature. The proposed algorithm has been used for reconstruction of UV at four Polish sites: Mikolajki, Kolobrzeg, Warszawa-Bielany and Zakopane since the early 1960s. Krzyscin's reconstruction of total ozone has been used in the calculations.

Facile and Low-Temperature Fabrication of Thermochromic Cr2O3/VO2 Smart Coatings: Enhanced Solar Modulation Ability, High Luminous Transmittance and UV-Shielding Function.

Science.gov (United States)

Chang, Tianci; Cao, Xun; Li, Ning; Long, Shiwei; Gao, Xiang; Dedon, Liv R; Sun, Guangyao; Luo, Hongjie; Jin, Ping

2017-08-09

In the pursuit of energy efficient materials, vanadium dioxide (VO 2 ) based smart coatings have gained much attention in recent years. For smart window applications, VO 2 thin films should be fabricated at low temperature to reduce the cost in commercial fabrication and solve compatibility problems. Meanwhile, thermochromic performance with high luminous transmittance and solar modulation ability, as well as effective UV shielding function has become the most important developing strategy for ideal smart windows. In this work, facile Cr 2 O 3 /VO 2 bilayer coatings on quartz glasses were designed and fabricated by magnetron sputtering at low temperatures ranging from 250 to 350 °C as compared with typical high growth temperatures (>450 °C). The bottom Cr 2 O 3 layer not only provides a structural template for the growth of VO 2 (R), but also serves as an antireflection layer for improving the luminous transmittance. It was found that the deposition of Cr 2 O 3 layer resulted in a dramatic enhancement of the solar modulation ability (56.4%) and improvement of luminous transmittance (26.4%) when compared to single-layer VO 2 coating. According to optical measurements, the Cr 2 O 3 /VO 2 bilayer structure exhibits excellent optical performances with an enhanced solar modulation ability (ΔT sol = 12.2%) and a high luminous transmittance (T lum,lt = 46.0%), which makes a good balance between ΔT sol and T lum for smart windows applications. As for UV-shielding properties, more than 95.8% UV radiation (250-400 nm) can be blocked out by the Cr 2 O 3 /VO 2 structure. In addition, the visualized energy-efficient effect was modeled by heating a beaker of water using infrared imaging method with/without a Cr 2 O 3 /VO 2 coating glass.

Total electron count variability and stratospheric ozone effects on solar backscatter and LWIR emissions

Science.gov (United States)

2017-03-10

heating occur. This method is achieved though measuring the intensity ratio of sky- scattered sunlight at a pair of UV wavelengths at solar zenith angles...cause impacts to direct-sun, UV, and zenith measurements . OOB light can affect the low intensity spectrum of solar light, which is not fully removed by...several key spectral properties that are pertinent to its measurement . Ozone is greenhouse gas that plays a primary role in the absorption of solar UV

The optimal UV exposure time for vitamin D3 synthesis and erythema estimated by UV observations in Korea

Science.gov (United States)

Lee, Y. G.; Koo, J. H.

2016-12-01

Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) from spectral UV measurements during 2006-2010. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied to the broadband UV measured by UV-Biometer at 6 sites in Korea Thus, the optimal UV exposure time for vitamin D3 synthesis and erythema was estimated for diurnal, seasonal, and annual scales over Korea. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice

Tm2+ luminescent materials for solar radiation conversion devices

NARCIS (Netherlands)

Van der Kolk, E.

2015-01-01

A solar radiation conversion device is described that comprises a luminescent Tm 2+ inorganic material for converting solar radiation of at least part of the UV and/or visible and/or infra red solar spectrum into infrared solar radiation, preferably said infrared solar radiation having a wavelength

Partial inhibition of in vitro pollen germination by simulated solar ultraviolet-B radiation

International Nuclear Information System (INIS)

Flint, S.D.; Caldwell, M.M.

1984-01-01

Pollen from four temperate-latitude taxa were treated with UV radiation in a portion of the UV-B (280-320 nm) waveband during in vitro germination. Inhibition of germination was noted in this pollen compared to samples treated identically except for the exclusion of the UV-B portion of the spectrum. Levels similar to maximum solar UV-B found in temperate-latitude areas failed to inhibit pollen germination significantly, while levels similar to maximum solar UV-B found in equatorial alpine locations caused partial inhibition of germination in three of the four taxa examined

An efficient visible and UV-light-activated B–N-codoped TiO2 photocatalytic film for solar depollution prepared via a green method

International Nuclear Information System (INIS)

Xu Qingchi; Zhang Yan; He Ziming; Loo, Say Chye Joachim; Tan, Timothy Thatt Yang

2012-01-01

This work reports an efficient visible and UV-light-activated boron and nitrogen codoped TiO 2 porous film prepared via a “green” and direct coating approach. Such photocatalyst is highly promising for solar depollution application due to its efficient photocatalytic activities in both visible and UV spectrum. The preparation method avoids the use of organic solvents, which are usually more expensive and hazardous compared with water. Using stearic acid as the model organic pollutant, the visible-light photocatalytic activity of optimized porous B–N-codoped TiO 2 film (p-3B–N–TiO 2 ) is 3 times higher than that of porous N-doped TiO 2 (p-N–TiO 2 ) film, while its UV photocatalytic activity is almost double that of p-N–TiO 2 film and comparable to that of porous TiO 2 . The enhancement in photocatalytic activity is attributed to higher surface area due to the porous structure, improved visible-light absorption attributed to interstitially substituted boron atoms, and coexistence of boron and nitrogen dopants which may reduce Ti 3+ recombination centers.

UV-B Radiation Contributes to Amphibian Population Declines

Science.gov (United States)

Blaustein, Andrew

2007-05-01

UV-B (280-315 nm) radiation is the most significant biologically damaging radiation at the terrestrial surface. At the organismal level, UV-B radiation can slow growth rates, cause immune dysfunction and result in sublethal damage. UV-B radiation can lead to mutations and cell death. Over evolutionary time, UV radiation has been an important stressor on living organisms. Natural events, including impacts from comets and asteroids, volcanic activity, supernova explosions and solar flares, can cause large-scale ozone depletion with accompanying increases in UV radiation. However, these natural events are transient. Moreover, the amount of ozone damage due to natural events depends upon a number of variables, including the magnitude of the event. This is different from modern-day human-induced production of chlorofluorocarbons (CFCs) and other chemicals that deplete stratospheric ozone continuously, resulting in long-term increases in UV-B radiation at the surface of the earth. We will briefly review the effects of UV-B exposure in one group of aquatic organisms_amphibians. UV-B has been implicated as a possible factor contributing to global declines and range reductions in amphibian populations.

Solar UVR instrument inter-comparison focussing on measurement interval recording setting and solar zenith angle as important factors

CSIR Research Space (South Africa)

Wright, GY

2015-09-01

Full Text Available considerations, to make meaningful deductions from the data. By comparing two solar UVR instruments, namely, a UV biometer and a Davis Vantage Pro2 UVR Detector, we look at an important factor influencing ambient solar UVR, namely SZA, and its impact... Vantage Pro2 UV detector comprises a transducer which is a semiconductor photodiode with a spectral response that matches the McKinley/Diffey Erythemal Action Spectrum. It includes a diffuser which provides good cosine response and multiple hard...

Characterization of ZnO coated polyester fabrics for UV protection

International Nuclear Information System (INIS)

Broasca, G.; Borcia, G.; Dumitrascu, N.; Vrinceanu, N.

2013-01-01

The textile industry aims to develop fabrics adapted to environmental conditions, in particular to UV radiation. Taking into account the demand for such materials, we prepare an inorganic–organic material, based on ZnO microparticles impregnation of polyester textiles, to perform combined UV-protection properties and high hydrophobicity. Scanning electron microscopy, UV reflectance, Impedance Spectroscopy, contact angle, air permeability, resistance to vapor transfer and tensile strength measurement are used for analysis of the surface and volume properties, related to the performance of the material under environmental conditions, as UV radiation, water and water vapors. The impregnation method ensures a good homogeneity and dispersion of ZnO microparticles into the textile polymeric matrix. The optimum level of impregnation of the fabrics is established to 3–5% ZnO, yielding stable properties, without overloading the fabric. The response of the coated polymer indicates better absorbing the UV radiation and dissipating the surface charge, time stability against UV and higher hydrophobic character, without modification of the mechanical properties, offering enhanced performance and comfort under environmental conditions.

Near-UV Transmittance of Basalt Dust as an Analog of the Martian Regolith: Implications for Sensor Calibration and Astrobiology

Directory of Open Access Journals (Sweden)

J. Martínez-Frías

2006-06-01

Full Text Available The Martian regolith is exposed to solar irradiation in the near-UV (200-390 nm.Basalt is one of the main components of the dust on Mars surface. The near-UV irradiationof basalt dust on Mars is simulated experimentally in order to determine the transmittance asa function of the mass and thickness of the dust. This data can serve to quantify theabsorption of dust deposited on sensors aiming to measure the UV intensity on Marssurface. The minimum thickness of the dust that corresponds to near-zero-transmittance inthe near-UV is measured. Hypothetical Martian microorganisms living on the dusty regolithat deeper layers would be preserved from the damaging solar UV irradiation.

Environmental stability study of holographic solar spectrum splitting materials

Science.gov (United States)

Chrysler, Benjamin D.; Ayala Pelaez, Silvana; Wu, Yuechen; Vorndran, Shelby D.; Kostuk, Raymond K.

2016-09-01

In this study the impact of outdoor temperature variations and solar illumination exposure on spectral filter material and holographic optical elements is examined. Although holographic components have been shown to be useful for solar spectrum splitting designs, relatively little quantitative data exist to demonstrate the extent to which these materials can withstand outdoor conditions. As researchers seek to investigate practical spectrum splitting designs, the environmental stability of holographic materials should be considered as an important factor. In the experiment presented, two holographic materials, Covestro Bayfol HX photopolymer and dichromated gelatin, and 3M reflective polymer filter materials are exposed to outdoor conditions for a period of several months. The environmental effect on absorption, spectral and angular bandwidth, peak efficiency, and Bragg matching conditions for the holograms are examined. Spectral bandwidth and transmittance of the 3M reflective filter material are also monitored. Holographic gratings are recorded, measured, and mounted on glass substrates and then sealed with a glass cover plate. The test samples are then mounted on a photovoltaic panel to simulate realistic temperature conditions and placed at an outdoor test facility in Tucson, Arizona. A duplicate set of holograms and 3M filter material is stored as a control group and periodically compared over the test period.

Flare activity on UV CETI: visible and IUE observations

International Nuclear Information System (INIS)

Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

1988-06-01

Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU = 2sup(m) but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings. The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

The Modern Solar House: Architecture, Energy, and the Emergence of Environmentalism, 1938--1959

Science.gov (United States)

Barber, Daniel A.

This dissertation describes the active discourse regarding solar house heating in American architectural, engineering, political, economic, and corporate contexts from the eve of World War II until the late 1950s. Interweaving these multiple narratives, the aim of the project is threefold: to document this vital discourse, to place it in the context of the history of architecture, and to trace through it the emergence of a techno-cultural environmentalism. Experimentation in the solar house relied on the principles of modern architecture for both energy efficiency and claims to cultural relevance. A passive "solar house principle" was developed in the late 30s in the suburban houses of George Fred Keck that involved open plans and flexible roof lines, and emphasized volumetric design. Spurred by wartime concern over energy resource depletion, architectural interest in solar heating also engaged an engineering discourse; in particular, an experimental program at the Massachusetts Institute of Technology led to four solar houses and a codification of its technological parameters. Attention to the MIT projects at the UN and in the Truman and Eisenhower administrations placed the solar house as a central node in an emergent network exploring the problems and possibilities of a renewable resource economy. Further experimentation elaborated on connections between this architecturalengineering discourse and the technical assistance regimes of development assistance; here by MIT researcher Maria Telkes, who also collaborated, at different junctures, with the architects Eleanor Raymond and Aladar Olgyay. The solar house discourse was further developed as a cultural project in the 1958 competition to design a solar heated residence, "Living With the Sun," which coalesced the diverse formal tendencies of midcentury modernism to promote the solar house as an innovation in both lifestyle and policy. Though the examples described are not successful as either technological

Development of a low cost UV index datalogger and comparison between UV index sensors

Science.gov (United States)

Gomes, L. M.; Ventura, L.

2018-02-01

Ultraviolet radiation (UVR) is the part of radiation emitted by the Sun, with range between 280 nm and 400 nm, and that reaches the Earth's surface. The UV rays are essential to the human because it stimulates the production of vitamin D but this radiation may be related to several health problems, including skin cancer and ocular diseases like pterygium, photokeratitis, cataract and more. To inform people about UV radiation, it is adopted the Ultraviolet Index (UVI). This UVI consists in a measure of solar UV radiation level, which contributes to cause sunburn on skin, also known as Erythema, and is indicated as an integer number between 1 and 14, associated to categories from low to extreme respectively. The aim of this work was to develop a low cost UVI datalogger capable of measuring three different UVI sensors simultaneously, record their data with timestamp and serve the measures online through a dedicated server, so general public can access their data and see the current UV radiation conditions. We also compared three different UVI sensors (SGlux UV cosine, Skye SKU440 and SiLabs SI1145) between them and with meteorological models during a period of months to verify their compliance. With five months data, we could verify the sensors working characteristics and decide which among them are the most suitable for research purposes.

Tertiary treatment of pulp mill wastewater by solar photo-Fenton

Energy Technology Data Exchange (ETDEWEB)

Lucas, Marco S., E-mail: mlucas@utad.pt [Centro de Quimica de Vila Real, Universidade de Tras-os-Montes e Alto Douro, Apartado 1013, 5001-801 Vila Real (Portugal); Peres, Jose A.; Amor, Carlos [Centro de Quimica de Vila Real, Universidade de Tras-os-Montes e Alto Douro, Apartado 1013, 5001-801 Vila Real (Portugal); Prieto-Rodriguez, Lucia; Maldonado, Manuel I.; Malato, Sixto [Plataforma Solar de Almeria (CIEMAT), Carretera de Senes, Km 4, 04200, Tabernas, Almeria (Spain)

2012-07-30

Highlights: Black-Right-Pointing-Pointer We firstly report a real pulp mill wastewater treatment by solar photo-Fenton in a CPC reactor. Fenton reagent experiments were tested firstly. Black-Right-Pointing-Pointer Solar photo-Fenton presents excellent ability to treat the pulp mill wastewater. Black-Right-Pointing-Pointer Experimental conditions were optimised. Black-Right-Pointing-Pointer Biodegradability and toxicity tests (respirometry assays and BOD{sub 5}/COD ratio) were performed during the wastewater treatment. Black-Right-Pointing-Pointer A way to reduce the economic and environmental impact was evaluated. - Abstract: This work reports on pulp mill wastewater (PMW) tertiary treatment by Fenton (Fe{sup 2+}/H{sub 2}O{sub 2}) and solar photo-Fenton (Fe{sup 2+}/H{sub 2}O{sub 2}/UV) processes in a pilot plant based on compound parabolic collectors (CPCs). Solar photo-Fenton reaction is much more efficient than the respective dark reaction under identical experimental conditions. It leads to DOC mineralisation, COD and total polyphenols (TP) removal higher than 90%. The solar photo-Fenton experiment with 5 mg Fe L{sup -1} reaches 90% of DOC mineralisation with 31 kJ L{sup -1} of UV energy and 50 mM of H{sub 2}O{sub 2}. The initial non-biodegradability of PMW, as shown by respirometry assays and BOD{sub 5}/COD ratio, can be changed after a solar photo-Fenton treatment. Experiments with 20 and 50 mg Fe L{sup -1} revealed that solar photo-Fenton can reach the same DOC degradation (90%), however, consuming less H{sub 2}O{sub 2} and time. Diluting the initial organic load to 50% also diminishes the dosage of H{sub 2}O{sub 2} and the necessary reaction time to achieve high DOC removals. Accordingly, solar photo-Fenton can be considered an alternative or complementary process to improve the performance of a biologic treatment and, subsequently, achieve legal limits on discharge into natural waters.

Cytoprotective effect against UV-induced DNA damage and oxidative stress: role of new biological UV filter.

Science.gov (United States)

Said, T; Dutot, M; Martin, C; Beaudeux, J-L; Boucher, C; Enee, E; Baudouin, C; Warnet, J-M; Rat, P

2007-03-01

The majority of chemical solar filters are cytotoxic, particularly on sensitive ocular cells (corneal and conjunctival cells). Consequently, a non-cytotoxic UV filter would be interesting in dermatology, but more especially in ophthalmology. In fact, light damage to the eye can be avoided thanks to a very efficient ocular antioxidant system; indeed, the chromophores absorb light and dissipate its energy. After middle age, a decrease in the production of antioxidants and antioxidative enzymes appears with accumulation of endogenous molecules that are phototoxic. UV radiations can induce reactive oxygen species formation, leading to various ocular diseases. Because most UV filters are cytotoxic for the eye, we investigated the anti-UV properties of Calophyllum inophyllum oil in order to propose it as a potential vehicle, free of toxicity, with a natural UV filter action in ophthalmic formulation. Calophyllum inophyllum oil, even at low concentration (1/10,000, v/v), exhibited significant UV absorption properties (maximum at 300nm) and was associated with an important sun protection factor (18-22). Oil concentrations up to 1% were not cytotoxic on human conjunctival epithelial cells, and Calophyllum inophyllum oil appeared to act as a cytoprotective agent against oxidative stress and DNA damage (85% of the DNA damage induced by UV radiations were inhibited with 1% Calophyllum oil) and did not induce in vivo ocular irritation (Draize test on New Zealand rabbits). Calophyllum inophyllum oil thus exhibited antioxidant and cytoprotective properties, and therefore might serve, for the first time, as a natural UV filter in ophthalmic preparations.

Long-term structural canopy changes sustain net photosynthesis per ground area in high arctic Vaccinium uliginosum exposed to changes in near-ambient UV-B levels

DEFF Research Database (Denmark)

Boesgaard, Kristine Stove; Albert, Kristian Rost; Ro-Poulsen, Helge

2012-01-01

Full recovery of the ozone layer is not expected for several decades and consequently, the incoming level of solar ultraviolet-B (UV-B) will only slowly be reduced. Therefore to investigate the structural and photosynthetic responses to changes in solar UV-B we conducted a 5-year UV-B exclusion s...

Solar ultraviolet-B radiation affects seedling emergence, DNA integrity, plant morphology, growth rate, and attractiveness to herbivore insects in Datura ferox

International Nuclear Information System (INIS)

Ballare, C.L.; Scopel, A.L.; Stapleton, A.E.

1996-01-01

To study functional relationships between the effects of solar ultraviolet-B radiation (UV0B) on different aspects of the physiology of a wild plant, we carried out exclusion experiments in the field with the summer annual Datura ferrox L. Solar UV-B incident over Buenos Aires reduced daytime seedling emergence, inhibited stem elongation and leaf expansion, and tended to reduce biomass accumulation during early growth. However, UV-B had no effect on calculated net assimilation rate. Using a monoclonal antibody specific to the cyclobutane-pyrimidine dimer (CPD), we found that plants receiving full sunlight had more CPDs per unit of DNA than plants shielded from solar UV-B, but the positive correlation between UV-B and CPD burden tended to level off at high (near solar) UV-B levels. At our field site, Datura plants were consumed by leaf beetles (Coleoptera), and the proportion of plants attacked by insects declined with the amount of UV-B received during growth. Field experiments showed that plant exposure to solar UV-B reduced the likelihood of leaf beetle attack by one-half. Our results highlight the complexities associated with scaling plant responses to solar UV-B, because they show: (a) a lack of correspondence between UV-B effects on net assimilation rate and whole-plant growth rate, (b) nonlinear UV-B dose-response curves, and (c) UV-B effects of plant attractiveness to natural herbivores. 56 refs., 7 figs

Solar Backscatter UV (SBUV total ozone and profile algorithm

Directory of Open Access Journals (Sweden)

P. K. Bhartia

2013-10-01

Full Text Available We describe the algorithm that has been applied to develop a 42 yr record of total ozone and ozone profiles from eight Solar Backscatter UV (SBUV instruments launched on NASA and NOAA satellites since April 1970. The Version 8 (V8 algorithm was released more than a decade ago and has been in use since then at NOAA to produce their operational ozone products. The current algorithm (V8.6 is basically the same as V8, except for updates to instrument calibration, incorporation of new ozone absorption cross-sections, and new ozone and cloud height climatologies. Since the V8 algorithm has been optimized for deriving monthly zonal mean (MZM anomalies for ozone assessment and model comparisons, our emphasis in this paper is primarily on characterizing the sources of errors that are relevant for such studies. When data are analyzed this way the effect of some errors, such as vertical smoothing of short-term variability, and noise due to clouds and aerosols diminish in importance, while the importance of others, such as errors due to vertical smoothing of the quasi-biennial oscillation (QBO and other periodic and aperiodic variations, become more important. With V8.6 zonal mean data we now provide smoothing kernels that can be used to compare anomalies in SBUV profile and partial ozone columns with models. In this paper we show how to use these kernels to compare SBUV data with Microwave Limb Sounder (MLS ozone profiles. These kernels are particularly useful for comparisons in the lower stratosphere where SBUV profiles have poor vertical resolution but partial column ozone values have high accuracy. We also provide our best estimate of the smoothing errors associated with SBUV MZM profiles. Since smoothing errors are the largest source of uncertainty in these profiles, they can be treated as error bars in deriving interannual variability and trends using SBUV data and for comparing with other measurements. In the V8 and V8.6 algorithms we derive total

Treatment of landfill leachate using Solar UV facilitated ...

African Journals Online (AJOL)

The use of heterogeneous photocatalytic degradation for the treatment of landfill leachate was investigated in this study. The photocatalytic degradation studies were carried out using Zinc oxide (ZnO) as photocatalyst and the process was facilitated by ultra violet radiation (UV) from sunlight. Characterisation of the raw ...

Possibilities of using solar energy for solving environmental problems

International Nuclear Information System (INIS)

Allouache, A.; Brakeni, A.; Skrabalek, P.; Ornst, J.

2012-01-01

In this paper there are discussed the possibilities of using solar energy to power supply of electron accelerators that can be used to solve environmental problems, such as sewage treatment and radiation sterilization. Algeria, due to geographical location, has one of the largest 'solar deposits' around the world. Insolation time exceeds 2,000 hours per year and may reach up to 3,900 hours per year on the High Plains and the Sahara. Daily energy that falls on a horizontal surface one square meter is about 5 KWh on the most territory of Algeria, i.e. approximately 1,700 kWh per m 2 per year in the North and 2,263 kWh per m 2 per year in the south. Independent energy sources from the Sun can also bring economic development of the Sahara region.

77 FR 46768 - Notice of Intent To Prepare an Environmental Impact Statement for the Moapa Solar Energy Center...

Science.gov (United States)

2012-08-06

... Impact Statement for the Moapa Solar Energy Center on the Moapa River Indian Reservation, Clark County NV... Environmental Impact Statement (EIS) that evaluates a solar energy generation center on the Moapa River Indian... . SUPPLEMENTARY INFORMATION: The Proposed Action consists of constructing and operating a solar generation energy...

Inhibition and recovery of semiconservative DNA synthesis in normal and solar UV sensitive ICR 2A frog cell lines following the induction of non-dimer DNA damage by sunlamp UV > 315 nm

Energy Technology Data Exchange (ETDEWEB)

Rosenstein, B.S. (Brown Univ., Providence, RI (USA). Dept. of Radiation Medicine)

1989-08-01

Cultures of solar UV-sensitive cell lines DRP 36 and DRP 153, and of the parental ICR 2A cell line, were exposed to 150 kJ/m{sup 2} of sunlamp UV>315nm plus photoreactivating light, resulting in the induction primarily of non-dimer DNA damage. Following either 0, 3, 6, 12 or 24 h incubation, cultures were pulse-labelled with ({sup 3}H) thymidine, and the synthesis of different size classes of replicon intermediates measured using alkaline step elution assay. For all three cell lines tested, an immediate depression of low molecular weight DNA synthesis was observed, followed by inhibition of all size classes of replicon intermediates. Within 12 h following irradiation, recovery of DNA synthesis was observed, generally most apparent for low molecular weight DNA. The ICR 2A cells exhibited a nearly full recovery in all size classes of DNA synthesized by 24 h. A much smaller recovery of continued inhibition was primarily in the synthesis of full replicon size DNA, and most pronounced for DRP 36 cells. (author).

Complementary UV-Absorption of Mycosporine-like Amino Acids and Scytonemin is Responsible for the UV-Insensitivity of Photosynthesis in Nostoc flagelliforme

Science.gov (United States)

Ferroni, Lorenzo; Klisch, Manfred; Pancaldi, Simonetta; Häder, Donat-Peter

2010-01-01

Mycosporine-like amino acids (MAAs) and scytonemin are UV-screening compounds that have presumably appeared early in the history of life and are widespread in cyanobacteria. Natural colonies of the UV-insensitive Nostoc flagelliforme were found to be especially rich in MAAs (32.1 mg g DW−1), concentrated in the glycan sheath together with scytonemin. MAAs are present in the form of oligosaccharide-linked molecules. Photosystem II activity, measured using PAM fluorescence and oxygen evolution, was used as a most sensitive physiological parameter to analyse the effectiveness of UV-protection. Laboratory experiments were performed under controlled conditions with a simulated solar radiation specifically deprived of UV-wavebands with cut-off filters (295, 305, 320, 345 and 395 nm). The UV-insensitivity of N. flagelliforme was found to cover the whole UV-A (315–400 nm) and UV-B (280–320 nm) range and is almost certainly due to the complementary UV-absorption of MAAs and scytonemin. The experimental approach used is proposed to be suitable for the comparison of the UV-protection ability in organisms that differ in their complement of UV-sunscreen compounds. Furthermore, this study performed with a genuinely terrestrial organism points to the relevance of marine photoprotective compounds for life on Earth, especially for the colonization of terrestrial environments. PMID:20161974

Complementary UV-Absorption of Mycosporine-like Amino Acids and Scytonemin is Responsible for the UV-Insensitivity of Photosynthesis in Nostoc flagelliforme

Directory of Open Access Journals (Sweden)

Donat-Peter Häder

2010-01-01

Full Text Available Mycosporine-like amino acids (MAAs and scytonemin are UV-screening compounds that have presumably appeared early in the history of life and are widespread in cyanobacteria. Natural colonies of the UV-insensitive Nostoc flagelliforme were found to be especially rich in MAAs (32.1 mg g DW-1, concentrated in the glycan sheath together with scytonemin. MAAs are present in the form of oligosaccharide-linked molecules. Photosystem II activity, measured using PAM fluorescence and oxygen evolution, was used as a most sensitive physiological parameter to analyse the effectiveness of UV-protection. Laboratory experiments were performed under controlled conditions with a simulated solar radiation specifically deprived of UV-wavebands with cut-off filters (295, 305, 320, 345 and 395 nm. The UV-insensitivity of N. flagelliforme was found to cover the whole UV-A (315–400 nm and UV-B (280–320 nm range and is almost certainly due to the complementary UV-absorption of MAAs and scytonemin. The experimental approach used is proposed to be suitable for the comparison of the UV-protection ability in organisms that differ in their complement of UV-sunscreen compounds. Furthermore, this study performed with a genuinely terrestrial organism points to the relevance of marine photoprotective compounds for life on Earth, especially for the colonization of terrestrial environments.

Flare activity on UV Ceti: visible and IUE observations

International Nuclear Information System (INIS)

Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

1988-01-01

Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU=2 mag but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings (∼ 100 km s -1 ). The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

UV astronomy throughout the ages: a historical perspective

Science.gov (United States)

Linsky, Jeffrey L.

2018-05-01

Astronomers have long recognized the critical need for ultraviolet imaging, photometry and spectroscopy of stars, planets, and galaxies, but this need could not be satisfied without access to space and the development of efficient instrumentation. When UV measurements became feasible, first with rockets and then with satellites, major discoveries came rapidly. It is true in the UV spectral region as in all others, that significant increases in sensitivity, spectral resolution, and time domain coverage have led to significant new understanding of astrophysical phenomena. I will describe a selection of these discoveries made in each of three eras: (1) the early history of rocket instrumentation and Copernicus, the first UV satellite, (2) the discovery phase pioneered by the IUE, FUSE and EUVE satellites, and (3) the full flowering of UV astronomy with the successful operation of HST and its many instruments. I will also mention a few areas where future UV instrumentation could lead to new discoveries. This review concentrates on developments in stellar and interstellar UV spectroscopy; the major discoveries in galactic, extragalactic, and solar system research are beyond the scope of this review. The important topic of UV technologies and detectors, which enable the remarkable advances in UV astronomy are also not included in this review.

76 FR 41816 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Ocotillo Sol Solar...

Science.gov (United States)

2011-07-15

...] Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Ocotillo Sol Solar Project... (ROW) authorization request for the Ocotillo Sol Solar Energy Facility (Project), a 15-18 megawatt (MW... Ocotillo Sol Solar Project by any of the following methods: Mail: Noel Ludwig, California Desert District...

Environmental impact of thin-film GaInP/GaAs and multicrystalline silicon solar modules produced with solar electricity

NARCIS (Netherlands)

Mohr, N.; Meijer, A.; Huijbregts, M.A.J.; Reijnders, L.

2009-01-01

Background, aim, and scope: The environmental burden of photovoltaic (PV) solar modules is currently largely determined by the cumulative input of fossil energy used for module production. However, with an increased focus on limiting the emission of CO2 coming from fossil fuels, it is expected that

The environmental and public health benefits of achieving high penetrations of solar energy in the United States

International Nuclear Information System (INIS)

Wiser, Ryan; Millstein, Dev; Mai, Trieu; Macknick, Jordan; Carpenter, Alberta; Cohen, Stuart; Cole, Wesley; Frew, Bethany; Heath, Garvin

2016-01-01

We estimate the environmental and public health benefits that may be realized if solar energy cost reductions continue until solar power is competitive across the U.S. without subsidies. Specifically, we model, from 2015 to 2050, solar power–induced reductions to greenhouse gas (GHG) emissions, air pollutant emissions, and water usage. To find the incremental benefits of new solar deployment, we compare the difference between two scenarios, one where solar costs have fallen such that solar supplies 14% of the nation's electricity by 2030 and 27% by 2050, and a baseline scenario in which no solar is added after 2014. We monetize benefits, where credible methods exist to do so. We find that under these scenarios, solar power reduces GHG and air pollutants by ∼10%, from 2015 to 2050, providing a discounted present value of $56–$789 billion (central value of ∼$250 billion, equivalent to ∼2 ¢/kWh-solar) in climate benefits and $77–$298 billion (central value of $167 billion, or ∼1.4 ¢/kWh-solar) in air quality and public health benefits. The ranges reflect uncertainty within the literature about the marginal impact of emissions of GHG and air pollutants. Solar power is also found to reduce water withdrawals and consumption by 4% and 9%, respectively, including in many drought-prone states. - Highlights: • With feasible cost reductions, solar power can provide major environmental benefits. • U.S. electric-sector modeling indicates climate benefits worth ∼2 ¢/kWh-solar. • Further modeling indicates air quality public health benefits worth 1.4 ¢/kWh-solar. • Solar could reduce power-sector water withdrawals and consumption by 4% and 9%.

Microbial Activity Response to Solar Radiation across Contrasting Environmental Conditions in Salar de Huasco, Northern Chilean Altiplano.

Science.gov (United States)

Hernández, Klaudia L; Yannicelli, Beatriz; Olsen, Lasse M; Dorador, Cristina; Menschel, Eduardo J; Molina, Verónica; Remonsellez, Francisco; Hengst, Martha B; Jeffrey, Wade H

2016-01-01

In high altitude environments, extreme levels of solar radiation and important differences of ionic concentrations over narrow spatial scales may modulate microbial activity. In Salar de Huasco, a high-altitude wetland in the Andean mountains, the high diversity of microbial communities has been characterized and associated with strong environmental variability. Communities that differed in light history and environmental conditions, such as nutrient concentrations and salinity from different spatial locations, were assessed for bacterial secondary production (BSP, 3 H-leucine incorporation) response from short-term exposures to solar radiation. We sampled during austral spring seven stations categorized as: (a) source stations, with recently emerged groundwater (no-previous solar exposure); (b) stream running water stations; (c) stations connected to source waters but far downstream from source points; and (d) isolated ponds disconnected from ground sources or streams with a longer isolation and solar exposure history. Very high values of 0.25 μE m -2 s -1 , 72 W m -2 and 12 W m -2 were measured for PAR, UVA, and UVB incident solar radiation, respectively. The environmental factors measured formed two groups of stations reflected by principal component analyses (near to groundwater sources and isolated systems) where isolated ponds had the highest BSP and microbial abundance (35 microalgae taxa, picoeukaryotes, nanoflagellates, and bacteria) plus higher salinities and PO 4 3- concentrations. BSP short-term response (4 h) to solar radiation was measured by 3 H-leucine incorporation under four different solar conditions: full sun, no UVB, PAR, and dark. Microbial communities established in waters with the longest surface exposure (e.g., isolated ponds) had the lowest BSP response to solar radiation treatments, and thus were likely best adapted to solar radiation exposure contrary to ground source waters. These results support our light history (solar exposure

SOLAR VARIABILITY FROM 240 TO 1750 nm IN TERMS OF FACULAE BRIGHTENING AND SUNSPOT DARKENING FROM SCIAMACHY

International Nuclear Information System (INIS)

Pagaran, J.; Weber, M.; Burrows, J.

2009-01-01

The change of spectral decomposition of the total radiative output on various timescales of solar magnetic activity is of large interest to terrestrial and solar-stellar atmosphere studies. Starting in 2002, SCIAMACHY was the first satellite instrument to observe daily solar spectral irradiance (SSI) continuously from 230 nm (UV) to 1750 nm (near-infrared; near-IR). In order to address the question of how much UV, visible (vis), and IR spectral regions change on 27 day and 11 year timescales, we parameterize short-term SSI variations in terms of faculae brightening (Mg II index) and sunspot darkening (photometric sunspot index) proxies. Although spectral variations above 300 nm are below 1% and, therefore, well below the accuracy of absolute radiometric calibration, relative accuracy for short-term changes is shown to be in the per mill range. This enables us to derive short-term spectral irradiance variations from the UV to the near-IR. During Halloween solar storm in 2003 with a record high sunspot area, we observe a reduction of 0.3% in the near-IR to 0.5% in the vis and near-UV. This is consistent with a 0.4% reduction in total solar irradiance (TSI). Over an entire 11 year solar cycle, SSI variability covering simultaneously the UV, vis, and IR spectral regions have not been directly observed so far. Using variations of solar proxies over solar cycle 23, solar cycle spectral variations have been estimated using scaling factors that best matched short-term variations of SCIAMACHY. In the 300-400 nm region, which strongly contributes to TSI solar cycle change, a contribution of 34% is derived from SCIAMACHY observations, which is lower than the reported values from SUSIM satellite data and the empirical SATIRE model. The total UV contribution (below 400 nm) to TSI solar cycle variations is estimated to be 55%.

The effects of solar ultraviolet-B radiation on the growth and yield of barley are accompanied by increased DNA damage and antioxidant responses

International Nuclear Information System (INIS)

Mazza, C.A.; Battista, D.; Zima, A.M.; Szwarcberg-Bracchitta, M.; Giordano, C.V.; Acevedo, A.; Scopel, A.L.; Ballare, C.L.

1999-01-01

There is limited information on the impacts of present-day solar ultraviolet-B radiation (UV-B) on biomass and grain yield of field crops and on the mechanisms that confer tolerance to UV-B radiation under field conditions. We investigated the effects of solar UV-B on aspects of the biochemistry, growth and yield of barley crops using replicated field plots and two barley strains, a catalase (CAT)-deficient mutant (RPr 79/4) and its wild-type mother line (Maris Mink). Solar UV-B reduced biomass accumulation and grain yield in both strains. The effects on crop biomass accumulation tended to be more severe in RPr 79/4 (≈ 32% reduction) than in the mother line (≈ 20% reduction). Solar UV-B caused measurable DNA damage in leaf tissue, in spite of inducing a significant increase in UV-absorbing sunscreens in the two lines. Maris Mink responded to solar UV-B with increased CAT and ascorbate peroxidase (APx) activity. No effects of UV-B on total superoxide dismutase (SOD) activity were detected. Compared with the wild type, RPr 79/4 had lower CAT activity, as expected, but higher APx activity. Neither of these activities increased in response to UV-B in RPr 79/4. These results suggest that growth inhibition by solar UV-B involves DNA damage and oxidative stress, and that constitutive and UV-B-induced antioxidant capacity may play an important role in UV-B tolerance. (author)