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Impact of paint matrix composition and thickness of paint layer on the activity of photocatalytic paints

Homa P., Tryba B., Gęsikiewicz-Puchalska A.

Polish Journal of Chemical Technology

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2017

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Vol. 19, nr 1

113--119

EN

Silicate, acrylic and latex photocatalytic paints were analyzed in regards to impact of paint matrix composition and paint layer’s thickness on performance in two photocatalytic tests. These included performances in photocatalytic decomposition of benzo[a]pyrene (BaP) and assessment of photocatalytic activity through use of smart ink test. Silicate photocatalytic paints displayed lower photocatalytic activity in comparison to acrylic and latex photocatalytic paints in both tests, despite the similar content of nanocrystalline TiO2. Measurements of depth of UV light penetration through the paints layer were performed and it appeared, that more porous structure of coating resulted in deeper penetration of UV light. In the case of acrylic paint, the thickness of the photocatalytic layer was around 9 μm, but for silicate paint DR this thickness was higher, around 21 μm.

2

UV absorption reveals mycosporine-like amino acids (MAAs) in Tatra mountain lake phytoplankton

Ficek D., Dera J., Woźniak B.

Oceanologia

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2013

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No. 55 (3)

599--609

EN

Enhanced absorption of UV radiation, an effect characteristic of mycosporine-like amino acids (MAAs), is reported in samples of phytoplankton from six lakes in the Tatra Mountains National Park (Poland). It was demonstrated that the mass-specific UV absorption coefficients for the phytoplankton in these lakes increased with altitude above sea level. Based on a comparison with the phytoplankton of Alpine lakes, investigated earlier by other authors (cited in this paper), it may be inferred that the phytoplankton of Tatra mountain lakes produce MAAs, which protect plant cells from UV light, the intensity of which increases with altitude.

3

Dissolution profile of fullerene-doped mineral oil

Kalus P.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2010

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z. 63

21-22

EN

In the paper, a measurements of fullerene dissolution in mineral transformer oil are analized. The proposed method uses UV absorption as dissolution indicator.

4

Two models for absorption by coloured dissolved organic matter (CDOM)

Schwarz J. N., Kowalczuk P., Kaczmarek S., Cota G. F., Mitchell B. G., Kahru M., Chavez F. P., Cunningham A., McKee D., Gege P., Kishino M., Phinney D. A., Raine R.

Oceanologia

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2002

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No. 44 (2)

209-241

EN

The standard exponential model for CDOM absorption has been applied to data from diverse waters. Absorption at 440 nm (ag440) ranged between close to zero and 10 m-1, and the slope of the semilogarithmic absorption spectrum over a minimum range of 400 to 440 nm (s440) ranged between < 0.01 and 0.04 nm-1. No relationship was found between ag440 or s440 and salinity. Except in the southern Baltic, s440 was found to have a broad distribution (0.0165 š 0.0035), suggesting that it should be introduced as an additional variable in bio-optical models when ag440 is large. An alternative model for CDOM absorption was applied to available high quality UV-visible absorption spectra from the Wisla river (Poland). This model assumes that the CDOM absorption spectrum comprises distinct Gaussian absorption bands in the UV, similar to those of benzene. Five bands were fit to the data. The mean central energy of all bands was higher in early summer (E~7.2, 6.6, 6.4, 6.2 and 5.5 eV or 172, 188, 194, 200 and 226 nm) than in winter. The higher energy bands were found to decay in both height and width with increasing salinity, while lower energy bands broadened with increasing salinity. s440 was found to be correlated with shape parameters of the bands centred at 6.4 and 5.5 eV. While the exponential model is convenient for optical modelling and remote sensing applications, these results suggest that the Gaussian model offers a deeper understanding of chemical interactions affecting CDOM molecular structure.