Presence Of Ultraviolet Radiation Research Articles

Opportunities regarding the potential use of the self-cleaning concept within urban contemporary architecture in Romania

Contemporary urban architecture faces two important issues: degradation of buildings, caused by exposure to various environmental factors (air and water pollution, mainly generated by the fuels combustion used for transport and heating) and also the costs for repair, cleaning and maintenance of the buildings facades. Regarding the last mentioned aspects, recent research led to development of materials with self-cleaning potential and consequently pollution reduction. Self-cleaning concrete represents a state-of-the-art material with photocatalytic properties generated by the addition in its composition of nanomaterials like TiO2. Already known for its intrinsic photocatalytic character, TiO2 has the ability to catalyse the decomposition of organic substances like grease and dirt, facilitating their quick removal only by rainwater action. Therefore, a building façade made of TiO2-SiO2-containing material develops substantial savings regarding maintenance costs, water consumption and less detergents contamination due to its intrinsic super hydrophilic effect of the surface in the presence of UV radiation, leading to easy dirt removal when water reaches it. The aim of present paper is presenting the latest stage of worldwide research regarding the obtaining of self-cleaning concrete and also the possibility of adapting the concept to the actual Romanian architecture needs, as a sustainable solution for urban pollution reduction.

New Physical Approaches combined with nanoparticles in Leishmania major Treatment

Introduction: Cutaneous leishmaniasis is a mutual parasitic disease, which is endemic in some countries of the world. The use of common drugs has been restricted because of confirmed side effects and drug resistance. There are still serious challenges in the treatment of CL. Developing new therapeutic methods for leishmaniasis, besides obtaining a prompt treatment response that prevents lesions' progression and scarring, is a significant success in the treatment of the disease. Novel approaches such as nanotechnology have been applied as a therapeutic modality. This study aimed at evaluating the influence of three physical approaches combined with nanoparticles on promastigotes, amastigotes, and lesion-induced parasites. Materials and Methods: Leishmania promastigotes were treated with gold nanoparticles combined with different duration of the microwave with 2450 MHz frequency. So, the promastigotes treated with electroporation and ultraviolet irradiation in presence of silver and titanium dioxide nanoparticles respectively. Leishmania amastigotes were preserved by GNP and SNP with different conditions exposure of Microwave irradiation and electroporation. Ultraviolet irradiation in presence of silver nanoparticles used to reduce the size of lesion-induced parasites. Results: Promastigotes survival rate induced a significant decline in different conditions of all three approaches in the presence of nanoparticles in comparison to similar samples without there. The least survival of amastigotes was also recorded in the groups containing nanoparticles received the microwave and electroporation. In addition, the findings on parasite burden and size of lesions showed a significant difference between the treatment groups with SNPs and UV irradiation and control group. Conclusion: The finding emphasized to the utility of new approaches by nanotechnology could be useful for the treatment of cutaneous disease such as leishmaniasis. For validation of this statement need to more research and some studies have been planned for this aim.

Removal of Azithromycin from Aqueous Solution Using UV- Light Alone and UV Plus Persulfate (UV/Na2S2O8) Processes.

Azithromycin is among the broad-spectrum antibiotics that is widely available in various environmental systems and could have destructive effects on the ecosystem and human health due to its bacterial resistance. In this study, removal of azithromycin from wastewater using an advanced oxidation process of ultraviolet light with and without persulfate was investigated and effective parameters for the management of each of the processes were evaluated. The effect of different parameters including the concentration of Azithromycin antibiotic at levels 5, 15, 45 mgL-1; the concentration of persulfate at levels 1, 2, 4 mmol; pH at levels 5, 7, 9, contact time in 30, 60, 90 minute range of azithromycin removal was investigated. Ultraviolet light at a wavelength of 254 nanometers was used to irradiate the reactor. The results showed that azithromycin removal was significantly lower in the presence of ultraviolet radiation alone 58% with the removal efficiency than the case that ultraviolet radiation was used with sodium persulfate 98%. The best azithromycin removal conditions were obtained at the removal efficiency with the initial concentration of antibiotic 5 mgL-1, the concentration of persulfate 1mmol, and the contact time 30 min. and pH = 7. The rate of decrease in the concentration of residual azithromycin is increasing with increasing sodium persulfate concentration and decreasing the initial azithromycin concentration. This research can help to apply the integrated use of advanced oxidation processes to idealize decomposition-resistant compounds removal processes and to better understand the parameters affecting the removal.

Facile fabrication of ZnO—graphite composite thin films for ultraviolet photodetection

We present a facile method for the fabrication of ZnO-graphite composite thin films by using the technique of interface exfoliation. Natural graphite and ZnO are trapped at an oil-water interface, resulting in the exfoliation of graphite and formation of a composite. These thin films exhibit photoconductivity in the presence of ultraviolet radiation. The extent of the response and the time scales involved depend on the relative amount of ZnO and graphite, which is determined by fabrication conditions. We focus on using commercially available, non-toxic materials for the entire fabrication route.

Removal of 2-phenylbenzimidazole-5-sulfonic acid using heterogeneous photocatalysis

UV filters are classified as environmental pollutants (emerging pollutants). One of the most frequently detected UV filters in real samples is 2-phenylbenzimidazole-5-sulfonic acid (PBSA). It has been shown that conventional technologies applied in sewage treatment plants are not adapted for complete removal of sunscreen agents. Therefore, there is a trend to undertake activities leading to improvement of water quality by enhancing treatment methods. This is important due to the fact that in an aqueous environment, in the presence of UV radiation or sunlight irradation, PBSA generates reactive oxygen species that can damage the DNA of living organisms. The aim of study was to investigate an effect of pH and TiO2 on PBSA stability in the presence of UV radiation. It was found that the rate of PBSA degradation depends on the catalyst dose and pH of solution. The photocatalysis reaction was carried out in a Heraeus laboratory exposure set equipped with a 150 W mediumpressure mercury lamp. The course of PBSA degradation process as a function of time was monitored using UV/VIS spectrophotometer and liquid chromatograph equipped with UV-Vis detector.

The influence of moisture on the evolution of the microstructure of asphalt binders with aging

This paper presents results on the evolution of the macroscopic appearance and surface microstructure of asphalt binders aged in an accelerated weathering tester. Two binders used in hot mix asphalt and two binders used in warm mix asphalt were aged in the presence of UV radiation, heat, oxygen and moisture. The same binders were previously aged using the same protocol but without the presence of moisture. Analysis of images captured using atomic force microscopy showed significant differences in the microstructure of binders aged in the presence of moisture versus those that were aged without moisture. There was no consistent evolution in the microstructure features in the presence of moisture. The combined effects of moisture and UV radiation caused part of the binder to become soluble and be transported away, while the remaining part of the binder experienced cracking and discontinuities. This observation relays the vital role that these atmospheric agents play in the degradation and microstructural evolution of asphalt binders.

Sonochemical Synthesis, Thermal Behavior and Luminescent Properties of Copper(II) Supramolecular, a Precursor for Preparation of CuO Nanoparticles and the Study of their Photocatalytic Activity

A supramolecular complex formulated as [Cu(dipic)(H2O)2]n (1) (H2dipic = pyridine-2,6-dicarboxylic acid) was sonochemically synthesized and characterized using elemental analysis, FT-infrared spectroscopy (FT-IR), and single crystal X-ray diffraction (SC-XRD). The thermal behavior (TGA/DSC) and luminescent properties of 1 were also studied. Geometric parameters and energies of 1 were calculated using the 6-31G basis set and Gaussian 98 program. CuO nanoparticles were achieved by thermal decomposition of 1 at 600 °C. Next, FT-infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and nitrogen sorption technique were used to characterize the structure and physicochemical properties of the CuO nanoparticles which were used in the photocatalytic degradation of methyl orange (MO) in the presence of ultraviolet light in a Plexiglas reactor. The effects of irradiation time, methyl orange concentration, and irradiation intensity on the percentage of MO destroyed were investigated. The results showed that in the presence of ultraviolet irradiation and by optimizing irradiation time, color concentration, and irradiation intensity, CuO nanoparticles perform well in degrading methyl orange.

Phototoxic effects of two common marine fuels on the settlement success of the coral Acropora tenuis

Coral reefs are at risk of exposure to petroleum hydrocarbons from shipping spills and uncontrolled discharges during extraction. The toxicity of petroleum hydrocarbons can substantially increase in the presence of ultraviolet radiation (UVR), therefore spills in shallow coral reef environments may be particularly hazardous to reef species. Here we investigated the sensitivity of coral larvae (Acropora tenuis) to dissolved hydrocarbons from heavy fuel oil (HFO) and diesel in the absence and presence of UVR. Larval settlement success decreased with increasing concentrations of dissolved HFO, and co-exposure to UVR doubled the toxicity: 50% effect concentrations (EC50) decreased from 96 (−UVR) to 51 (+UVR) total petroleum aromatic hydrocarbons (TPAH). Toxic thresholds for HFO were similar to concentrations reported during marine spills: EC10s of 24 (−UVR) and 15 (+UVR) µg l−1. While less toxic, diesel also reduced settlement and exhibited phototoxicity: EC10s of 122 (+UVR) and 302 (−UVR) µg l−1. This study demonstrates that the presence of UVR increases the hazard posed by oil pollution to tropical, shallow-water coral reefs. Further research on the effects of oils in the presence of UVR is needed to improve the environmental relevance of risk assessments and ensure appropriate protection for shallow reef environments against oil pollution.

Corrosion protection performance of nanocomposite coatings under static, UV, and dynamic conditions

Silicone-modified epoxy polymeric matrix was successfully fabricated and reinforced with 1–2 wt% SiO2, TiO2, and TiSiO4 nanoparticles. Fourier-transform infrared spectroscopy, contact angle measurements, differential scanning calorimetry, and field-emission scanning electron microscopy together with energy-dispersive X-ray spectroscopy were employed to investigate different characteristics of the prepared coatings. To simulate operating conditions, all samples were characterized via electrochemical impedance spectroscopy (EIS) after being subjected to different conditions. Corrosion under static conditions, in which the samples were exposed to a static electrolyte without further change in other parameters, was investigated. Furthermore, to study the effects of ultraviolet (UV) radiation in accelerating the degradation of the coatings, samples were characterized after being subjected to UV while immersed statically in the electrolyte. Additionally, the corrosion protection performance was investigated after subjecting the coated substrates to dynamic conditions involving continuous movement of the sample in the electrolyte, simulating continuous wear of the coated surfaces. Compared with the static condition, the EIS results revealed the vital role of the silicone resin and nanoparticles in improving the stability of the coating film against corrosion degradation in the presence of UV radiation, while poor performance in dynamic condition was recorded for all the coating systems.

Phototoxic effects of PAH and UVA exposure on molecular responses and developmental success in coral larvae

Exposure to polycyclic aromatic carbons (PAHs) poses a growing risk to coral reefs due to increasing shipping and petroleum extraction in tropical waters. Damaging effects of specific PAHs can be further enhanced by the presence of ultraviolet radiation, known as phototoxicity. We tested phototoxic effects of the PAHs anthracene and phenanthrene on larvae of the scleractinian coral Acropora tenuis in the presence and absence of UVA (320–400 nm). Activity of superoxide dismutase (SOD) enzyme was reduced by anthracene while phenanthrene and UVA exposure did not have any effect. Gene expression of MnSod remained constant across all treatments. The genes Catalase, Hsp70 and Hsp90 showed increased expression levels in larvae exposed to anthracene, but not phenanthrene. Gene expression of p53 was upregulated in the presence of UVA, but downregulated when exposed to PAHs. The influence on stress-related biochemical pathways and gene expresson in A. tenuis larvae was considerably greater for anthracene than phenanthrene, and UVA-induced phototoxicity was only evident for anthracene. The combined effects of UVA and PAH exposure on larval survival and metamorphosis paralleled the sub-lethal stress responses, clearly highlighting the interaction of UVA on anthracene toxicity and ultimately the coral’s development.

Individual and simultaneous degradation of antibiotics sulfamethoxazole and trimethoprim by UV and solar radiation in aqueous solution using bentonite and vermiculite as photocatalysts

Abstract This work is aimed at studying the utilization of bentonite and vermiculite as a photocatalyst in the individual and simultaneous degradation of sulfamethoxazole (SMX) and trimethoprim (TMP) by UV and solar light radiation. The clays were characterized by various analytical techniques, and it was corroborated that the photoactivity and textural properties of clays remained unaffected by the UV radiation. The band gap energy (Eg) of both clays was less than 4 eV, revealing that they could behave as semiconductor materials and could act as photoactive materials in the presence of UV radiation. The photodegradation rate and the maximum percentage of degradation for SMX and TMP were markedly enhanced by the presence of the clays. The reaction rate constant for SMX and TMP degradation in UV radiation was increased 11.4 and 46.4 times, respectively, when 10 mg of vermiculite were added to the UV system. Better degradation results were observed by using vermiculite, and this trend could be attributed to the higher percentage of doping ions in the vermiculite. In the UV radiation and UV/Clay systems, the rate constants for single degradation were faster than those for simultaneous degradation of SMX and TMP; this was due to the competition of SMX and TMP for the generated oxidant radicals. The photoactivity of the reutilized clays was similar to that of the original clays.

Impacts of UV Radiation on the Polymorphic Transformation of β Glycine to α Glycine

AbstractThe influence of UV radiation on the phase transformation of β glycine to α glycine was investigated at 25 °C in the absence and the presence of varying intensities of UV radiation. The transformation of the polymorph was monitored by continuously measuring the ultrasonic velocity in the crystallizer, and the crystals obtained were analyzed using XRD to determine the polymorphic form. In addition, the crystals were characterized by SEM, a particle sizer and ATR–FTIR. The results indicated that the UV radiation and its intensity have significant effects on the both the average particle size and the morphology of glycine crystals. To further understand the role of UV radiation and its intensity on glycine phase transformation, these experiments were also performed in the presence of propane‐1,2,3‐tricarboxylic acid. It was found that the presence of the additive in the crystallization media caused the transition time to be extended; however, the presence of both the additive and UV radiation lessened the phase transformation time significantly, depending on the increase in UV radiation intensity. In addition, TGA–MS results revealed that the amount of evolved gases in the presence of UV radiation was reduced, and that the UV radiation caused changes in the glycine.

Combined effects of UVR and nutrients on cell ultrastructure, photosynthesis and biochemistry in Gracilariopsis longissima (Gracilariales, Rhodophyta)

The combined effects of ultraviolet radiation (UVR) and nutrients on the red macroalga Gracilariopsis longissima were analyzed for 14days in a 2×2 factorial experiment design. Cell ultrastructure, photosynthetic activity as in vivo chlorophyll a fluorescence and the accumulation of bioactive compounds as soluble proteins, starch, lipids, polyphenols and mycosporine-like amino acids (MAAs) were evaluated. Three main morphological alterations as defense mechanisms against UVR were observed, i.e., an increase in cell wall thickness, accumulation of floridean starch grains and multiplication of the number of layers of cortical cells. Interaction of light and nutrients affected photosynthetic variables, such as electron transport rate (estimator of photosynthetic capacity) and photoinhibition irradiance (Eopt), and also the level of N compounds (i.e., proteins and MAAs) and total carbon and polyphenol content. Other variables such as chlorophyll a, carotenoids, starch, lipids, antioxidant activity and cell viability were influenced by both factors, or only by light, but without interactive effects. G. longissima showed a high acclimation to elevated UVR and nutrients by the decrease of the photosynthetic rate and the increase in the accumulation of N compounds with photoprotection and antioxidant capacities. On the other hand, starch, lipid and polyphenols increased mainly in the presence of UVR under low nutrient availability. The biotechnological implications of the metabolic changes due to N availability and UVR in this species are discussed.

Multifunctional performance of nanocrystalline tin oxide

Crystalline tin oxide, with nanometre size range in diameter, was synthesized using a solution phase approach. The oxide material showed the photocatalytic performance for the reduction of a xanthene based dye in presence of ultra-violet irradiation, where the conduction band electron is responsible for the reduction mechanism. In addition to that the calculated power density and energy density values of the synthesized tin oxide nanoparticles, in combination with graphitic carbon, is comparable with the electrochemical supercapacitor like materials.

Removal of benzotriazole by Photo-Fenton like process using nano zero-valent iron: response surface methodology with a Box-Behnken design

Abstract In this paper, the removal of benzotriazole (BTA) was investigated by a Photo-Fenton process using nano zero valent iron (NZVI) and optimization by response surface methodology based on Box-Behnken method. Effect of operating parameters affecting removal efficiency such as H2O2, NZVI, and BTA concentrations as well as pH was studied. All the experiments were performed in the presence of ultraviolet radiation. Predicted levels and BTA removal were found to be in good agreement with the experimental levels (R2 = 0. 9500). The optimal parameters were determined at 60 min reaction time, 15 mg L-1 BTA, 0.10 g L-1 NZVI, and 1.5 mmol L-1 H2O2 for Photo-Fenton-like reaction. NZVI was characterized using X-ray diffraction (XRD), transmission electron microscope (TEM) images, and scanning electron microscope (SEM) analysis.

High levels of solar radiation offset impacts of ocean acidification on calcifying and non-calcifying strains of Emiliania huxleyi

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 568:47-58 (2017) - DOI: https://doi.org/10.3354/meps12042 High levels of solar radiation offset impacts of ocean acidification on calcifying and non-calcifying strains of Emiliania huxleyi Peng Jin1, Jiancheng Ding1, Tao Xing1, Ulf Riebesell2, Kunshan Gao1,* 1State Key Laboratory of Marine Environmental Science/College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China 2GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany *Corresponding author: ksgao@xmu.edu.cn ABSTRACT: Coccolithophores, a globally distributed group of marine phytoplankton, showed diverse responses to ocean acidification (OA) and to combinations of OA with other environmental factors. While their growth can be enhanced and calcification be hindered by OA under constant indoor light, fluctuation of solar radiation with ultraviolet irradiances might offset such effects. In this study, when a calcifying and a non-calcifying strain of Emiliania huxleyi were grown at 2 CO2 concentrations (low CO2 [LC]: 395 µatm; high CO2 [HC]: 1000 µatm) under different levels of incident solar radiation in the presence of ultraviolet radiation (UVR), HC and increased levels of solar radiation acted synergistically to enhance the growth in the calcifying strain but not in the non-calcifying strain. HC enhanced the particulate organic carbon (POC) and nitrogen (PON) productions in both strains, and this effect was more obvious at high levels of solar radiation. While HC decreased calcification at low solar radiation levels, it did not cause a significant effect at high levels of solar radiation, implying that a sufficient supply of light energy can offset the impact of OA on the calcifying strain. Our data suggest that increased light exposure, which is predicted to happen with shoaling of the upper mixing layer due to progressive warming, could counteract the impact of OA on coccolithophores distributed within this layer. KEY WORDS: Ocean acidification · Fluctuating light · UV radiation · Coccolithophore · Calcification Full text in pdf format Supplementary material PreviousNextCite this article as: Jin P, Ding J, Xing T, Riebesell U, Gao K (2017) High levels of solar radiation offset impacts of ocean acidification on calcifying and non-calcifying strains of Emiliania huxleyi. Mar Ecol Prog Ser 568:47-58. https://doi.org/10.3354/meps12042 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 568. Online publication date: March 24, 2017 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2017 Inter-Research.

Actividad fotocatalítica de películas de TiO₂ sensibilizadas con complejos metálicos

Se efectuó un análisis de las películas de TiO2 sensibilizadas con complejos metálicos de níquel y cobalto (II) contenidos en ligandos derivados del 3.5-dimetilpirazol. Se realizó un estudio preliminar del efecto del protocolo de limpieza de sustrato y de la temperatura de calcinación de las películas de TiO2 sin modificar. Se llevó a cabo la modificación de las películas con el método de dip coating variando el solvente utilizado en la dilución de los complejos y el tiempo del tratamiento térmico posterior a la modificación. Finalmente se evaluó la actividad fotocatalítica de las películas modificadas mediante la degradación de azul de metileno en presencia de radiación ultravioleta y luz visible.

Electron excitation of a surface by atoms from hydrogen plasma in the presence of ultraviolet radiation

The dependence describing the probability of the electron excitation of a crystal by the energy of a chemical reaction on the energy of electron transitions is derived. It is found that the probability of electron chemoexcitation grows exponentially when the energy of electron transitions falls in the solid state. The efficiency of the nonadiabatic chemo-electronic conversion of energy in structures of hydrogen energetics based on Schottky diodes is calculated.

Development of a novel curing system for low temperature curing of resins with the aid of nanotechnology and ultraviolet radiation

In this research work, low temperature curing of crease recovery finishes was done with the help of ZnO nanoparticles as catalyst in the presence of UV radiation. The results were compared with the conventional catalyst and thermal curing system.

Corrosion behavior of TiO2-treated type 304 stainless steels in high temperature water containing with hydrogen peroxide

ABSTRACTTitanium dioxide (TiO2) treatment coupled with ultraviolet irradiation was selected as a corrosion mitigation technique for Type 304 stainless steel (SS) in high-temperature pure water with the presence of hydrogen peroxide (H2O2). Type 304 SS specimens were pre-oxidized in oxygenated pure water at 288 °C and then coated with TiO2 nanoparticles by hydrothermal deposition. Electrochemical polarization analyses were conducted to investigate the corrosion behavior of both TiO2-treated and pre-oxidized specimens in 288 °C pure water with 300 ppb H2O2. Ultraviolet (UV) irradiation was then imposed upon the TiO2-treated specimens to examine if there was any distinct photoelectric effect on the corrosion behavior of the treated samples. It was found that the electrochemical corrosion potentials of the TiO2 treated specimens under UV irradiation were 10–20 mV lower than those without UV. In addition, the corrosion current densities of the treated specimens were also lower in the presence of UV radiation. Without UV radiation, however, no significant differences were observed between the TiO2 treated and untreated specimens. These results indicate that the TiO2 treatment in combination with UV radiation would reduce the corrosion rate of Type 304 SS in H2O2-rich, high-temperature pure water.