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Made available in DSpace on 2022-04-28T19:42:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-08-14 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Multilayered TiO2/TiO2−x/TiO2 films, deposited by twenty periodical interruptions of O2 flow during reactive sputtering deposition were submitted to photocatalytic tests and characterized. The O2 flow interruptions lasted 10 s, 38 s, 45 s, and 70 s, while the regular flow periods lasted 540 s. The photocatalytic tests were performed using UV irradiation from a mercury lamp and a solution of methylene blue dye. The best photocatalytic response was observed in samples corresponding to 10 s interruptions. The results show that the amount of degraded dye was increased by an average of 1.67 times in the interrupted flow sample as compared to the homogeneous TiO2 film deposited under similar conditions. The results show that this relatively simple deposition procedure can produce significant improvements to the photocatalytic activity of the TiO2-based catalysts. Graphic abstract: [Figure not available: see fulltext.] School of Sciences Graduate Program in Materials Science and Technology - POSMAT Universidade Estadual Paulista – UNESP Physics Department Fundamental Sciences Division – IEF Instituto Tecnológico de Aeronáutica – ITA School of Sciences Graduate Program in Materials Science and Technology - POSMAT Universidade Estadual Paulista – UNESP FAPESP: 2017/18916-2

The photo-induced fluorescence method is often applied to determine non-native fluorescent compounds. It typically uses UV irradiation from a high pressure mercury vapor discharge lamp to create photo-induced fluorescent compounds, which are then quantified by fluorescence spectroscopy. However, these mercury lamps require a high-voltage power supply and may accidentally induce electric shocks and the release of mercury vapors. As an alternative, we have evaluated in this technical note new UV-C germicidal lamps. These lamps exhibit a higher power at 254 nm and allowed us to obtain a far greater amount of photo-induced compounds in a shorter time. For the first time, this new irradiation system has been applied for the determination of pesticides in water and has shown a significant increase in the method sensitivity. These good results allowed us to conclude that the new UV-C lamps are a relevant alternative to high pressure mercury vapor discharge lamps for use with photo induced fluorescent methods.

The yield of redox reactions (Fe2+ oxidation and Mn7+ reduction in aqueous solutions) under the action of hot plasma radiation in liquid and species formed in the region of plasma discharge was measured. The goal of the investigation is to evaluate the role of hot plasma radiation as active factor compared to species generating in discharge itself. As source of active species we studied the spark discharge in air and in nitrogen (SD50 generator), the generator of corona discharge in air and low-pressure mercury UV lamp (λ = 253.7 nm). The yield of redox reactions for all sources was determined using detecting liquids; the mechanisms of these reactions were analysed. It was shown that chain reactions do not take place. When the yields were calculated, the stoichiometry of the reactions was taken into account. An analysis of the results shows that under the action of a spark discharge generator SD50, the main active factor is radiation. The role of active species formed in discharge region not more than 15%. Under the action of a spark discharge radiation, active species first form in the sample being processed, and then interact with substances dissolved in water. There is an indirect mechanism of action. Owing of this peculiarity, the redox properties of water, activated by hot plasma radiation, are the same as direct treatment of samples to hot plasma radiation. For a corona discharge plasma and radiation from a mercury lamp, such a mechanism does not occur.

Direct photolysis of the emerging contaminant 2-(thiocyanomethylthio) benzothiazole (TMCTB) was performed in aqueous solution at different concentrations with high-pressure mercury lamp (5.0, 8.0, 13.0, 16.0, 20.0, 23.0, 27.0, 35.0, 40.0, 45.0, and 50.0 mg L− 1) and with natural sunlight radiation (6.0, 30.0, and 60.0 mg L− 1). TCMTB underwent rapid degradation by direct photolysis with a high-pressure mercury lamp in aqueous solutions, with 99% removal after 30 min at all concentrations studied. For sunlight photolysis, TCMTB degradation was observed with 96%, 81%, and 64% removal for initial concentrations of 6.0, 30.0, and 60.0 mg L− 1, respectively, after 7 h of exposure to sunlight. The degradation of TCMTB in lab-scale wastewater had kinetic constant and t1/2 in the same order when compared to the photodegradation of TCMTB in aqueous solutions. In addition, the results showed that photolysis with a high-pressure mercury lamp and sunlight were governed by the same kinetic order, however the kinetic parameters showed that degradation with sunlight was 40 times slower than photolysis with the mercury lamp. Twelve transformation products (TP) were identified, and eight of the TP have not been described in the literature. Furthermore, prediction of toxicity with ECOSAR software was carried out for fish, daphnids, and green algae species. It showed that photolytic treatment is efficient for reducing the toxicity of the compound, since the degradation formed compounds with lower toxicity than the primary compound. In conclusion, this study suggests that photolysis is an efficient way to remove the studied contaminant, and it highlights the potential of this technique for the degradation of emerging contaminants in industrial wastewater treatment plants.

This paper presented a facile and efficient HPTLC method for quantifying riboflavin fortification in rice noodle that was a staple food popular in Asian countries. After high-throughput separation on silica gel plates with methanol/ethyl acetate/triethylamine (3/7/1, v/v/v) as the mobile phase, the obtained results were analyzed by fluorescence densitometry (mercury lamp, 360 nm excitation wavelength in combination with K400 optical filter). Quantification in this way offered high linearity (R2 = 0.9998 within 10–80 ng/band) and precision (RSD

A large number of fluorinated chemicals have been synthesized and used worldwide because of their unique properties. However, because of the strong C–F bond, fluorinated chemicals are not decomposed in nature. Herein, the activity of gallium oxide toward the degradation of trifluoromethyl benzoic acid in aqueous media was examined under UVC radiation by using a low-pressure mercury lamp as the light source. The degradation process was monitored by HPLC, UV–Vis spectroscopy and TOF-MS techniques, which permitted some intermediates to be identified. The defluorination efficiency was greater under a nitrogen atmosphere than in air, with the para-isomer (4-(trifluoromethyl)benzoic acid) being more prone to degradation (ca. 90%). The degradation mechanism was proposed on the basis of the theoretical calculation on the electron density and the intermediate analysis.

In this work, a novel CaS:Yb2+, Cl− Long Persistent Luminescence (LPL) phosphor was prepared by a solid-state reaction method in carbon reduction atmosphere. The Cl− ion was introduced to sensitize the luminescence of Yb2+ ion. The crystal structure was characterized by X-ray diffraction (XRD). The Photoluminescence (PL) and Photo-Stimulated Luminescence (PSL) properties of the as-prepared phosphors under the mercury lamp were systematically investigated. The bright red long afterglow in the range of 580–750 nm with a maximum at 650 nm has the high color purity and can last 5 min. It is worth mentioned that, in this phosphor, the attenuation of the afterglow luminescence is little in the first second. The CaS:Yb2+, Cl− with a luminescent center at 650 nm can be used to increase the color saturation of white alternating current (AC) LEDs by coating phosphor on a blue AC LED chip.

The direct coupling of 3-iodochromen-4-ones with heteroaromatics has been achieved via a photochemical reaction. A variety of 3-heteroarylchromones was obtained in moderate to good yields from the corresponding 3-iodochromen-4-ones and heteroaromatics, such as pyrrole, furan, thiophene, and benzofuran. The reaction worked smoothly in acetonitrile under a mercury lamp without any additives, providing a catalyst- and base-free approach for the synthesis of 3-heteroarylchromones.

Two conifers and two deciduous wood species were irradiated by strong UV emitter mercury lamp at elevated temperatures up to 160 °C. Other series of samples were treated in the same chamber at the same temperatures but without light. Results showed that UV light irradiation produced much greater discolouration at elevated temperatures above 80 °C than at ambient temperature. The combined light irradiation and thermal treatment at 160 °C generated much larger discolouration than the sum of the discolouration data caused by UV light irradiation at 30 °C and by pure thermal treatment at 160 °C. The thermal effect during photodegradation was not only the simple addition of two effects, but the elevated temperature multiplied the effect of photodegradation. The greatest difference was shown by the redness change. The Arrhenius plots of all tree colour coordinates had a breaking point close to 100 °C, showing that above this temperature the chemical changes are more complex than below this value.

The composition of the elements of a fluorescent lamp is described. The functions and requirements of the bulb, fluorescent coating, electrodes, and other parts of the lamp are presented. Improved technologies for manufacturing the elements of a compact fluorescent lamp that can significantly increase the quality and lifetime of manufactured lamps and significantly expand their practical applications are proposed.

Photodegradation is the major dissipation pathway for emamectin benzoate (EB) in water. Therefore, the photolysis of EB was studied in distilled water (DW) and methanol under different irradiation conditions such as natural sunlight, UV tube, and artificially stimulated light (mercury lamp 125 W). The results of the study showed that EB degrades rapidly in DW than in methanol as evidenced by a photodegradation efficiency of about 75 % achieved in DW, after 24 h of irradiation with UV light, while in methanol, it was only 59.3 %. The addition of iron to EB solution in DW further enhanced its photodegradation. The rate of photodegradation of EB was recorded to be increased from 5.5 × 10−2 to 1.0 × 10−1 k/h after amendment with iron. The order for the rate of photodegradation of EB was DW + Fe > DW > methanol, with their respective t 1/2 values of 6.5, 12.6, and 18.7 h. Fe amendment was also found to enhance the degradation efficiency of EB even in the absence of any light (dark).

The reagent-free mineralization of dissolved organic matter (DOM) in river water was achieved within 1 min using a lamp-pass-through photoreactor containing a narrow reaction tube (2 mm i.d.) passing through a 40 W mercury lamp. The structure efficiently irradiated the sample solution in the tube with vacuum ultraviolet (VUV; 185 nm) light from the lamp, which rapidly decomposed the DOM with hydroxyl radicals generated efficiently from the water and oxygen that are naturally present in the solution. The photoreactor was also applicable to oxidizing reagent-free online toatal organic carbon (TOC) analysis of DOM in river-water samples using a non-dispersive infrared radiation detector after acidification of the sample using 20 mmol L(-1) phosphoric acid. The detection limit for phthalate at the injection of 390 μL was 6.2 μg of carbon L(-1). The repeatability, as expressed by the relative standard deviation, was 2.5% for thrice-repeated analyses of a river sample with 1.85 mg of carbon L(-1).

When O-(4-acyloxyanilinocarbonylmethyl)-4-tert-butylcalix[8]arene films were irradiated for 60 min with 254-nm UV light from a low-pressure mercury lamp, the calixarene derivative 1 underwent a highly selective photo-Fries rearrangement in the film state to yield the corresponding Fries-rearranged product 2 along with a minor amount of the fragmentation product 3. This photochemical rearrangement enhanced the refractive index of the films by as much as 0.015.

Thermal analysis of YxEu1−xVO4 powder (used as “phosphor” coating for a high pressure mercury lamp) was done under a non-isothermal linear regime, both in a dynamic air regime and in a nitrogen atmosphere. The heating in air atmosphere gave on TG curve small rate of mass increase due to oxygenation and two endothermic effects are observed on DTA and DSC curves. By contrary, in nitrogen atmosphere a continuous stepped mass loss of powder (around 0.65 %), is recorded in the range of temperatures from room temperatures to 1,200 °C, and only one endothermic effect, to eliminate the gases accumulated on the crystallite surface. The powder was heated for 3 h in a Nabertherm furnace at 350, 800, and 1,100 °C using quite similar rate for heating program followed by a furnace cooling to room temperature. XRD and FTIR analyses showed the sample purification by thermal treatment and a very small increase of nanocrystallite sizes. The time evolution of the optical emission spectra in the range from 186.2 to 877.47 nm were recorded for different lamp powers in two different situations: with the outer bulb coated with YxEu1−xVO4 type “phosphor”, and without it. We observed that UV-Hg lines are absorbed by YxEu1−xVO4 type “phosphor” with different percents (100 % for 253.73 nm, 95 % for 312.65 nm, and 33 % for 365.12 nm) but the heating of the powder do not influence the UV-absorption properties of the powder.

Photoirradiation of Me2CO–H2O solution of pent-4-en-1-ol (1a) with a high-pressure mercury lamp in a test tube gave 8-hydroxyoctan-2-one (3a) in 66 % yield along with oxetane (4a) and the isomer (4a′) in 10 % yield. Irradiation of the running Me2CO–H2O solution of 1a in the flow system of a microchannel reactor (MCR) gave mainly 4a. The photoreaction of 1,1-diphenylethene (2a) with triethylamine gave a Markovnikov-type adduct (5a) and an anti-Markovnikov-type adduct (6a). The use of the MCR enhanced the production of 5a. These phenomena were explained by the light-path length effects of the MCR.

A novel UV apparatus based on Dean vortex technology is designed for inactivating bacteria in milk. In this apparatus, the milk flows through a helical quartz tube coiling around an electrodeless UV lamp (EUL) with a radio frequency of 2.65 MHz. Flow rate, inner diameter of quartz tube, different UV sources, and different types of bacteria have been found as the key factors for the valuable effects on bacterial inactivation. The EUL apparatus worked more efficiently in the UV inactivation of the predetermined populations of milk-related bacteria than the conventional low-pressure high-intensity mercury lamp. When the UV dose of 21.3 mJ/cm2 was applied, the numbers of all the bacteria were reduced by more than 6 log10 with a flow rate of 28.8 L/h and a tube’s inner diameter of 1.5 mm. Dean vortices were formed in the milk flow during the UV processing and played an important role in the UV inactivation of the bacteria. Another inactivation test with the apparatus applying the UV dose of 21.3 mJ/cm2 was also done with raw cow’s milk containing indigenous microorganisms, including Salmonella and Shigella spp., Listeria monocytogenes, Staphylococcus spp., Enterobacteriaceae, lactic acid bacteria, pseudomonads, and the total aerobic bacteria were reduced by approximately 3–4 log10. In short, the EUL apparatus requires smaller energy, occupies less space, and has simpler operating procedures than thermal pasteurization. Thus, the novel method provides a viable alternative to thermal pasteurization of milk for improving the microbial safety of milk and extending its shelf life.

Using carbon felt, polytetrafluoroethylene latex and powder catalyst to assembly a light energy conversion device, the photocatalytic activity of catalyst 2.0%WO3-TiO2 (2%WO3 compounding TiO2) with oxygen vacancies was studied through the water splitting for O2 evolution, using a high pressure mercury lamp as the light source and Fe3+ as the electron acceptor in two different devices: an ordinary photolysis device with catalyst powder suspending through a magnetic stirrer and a self-assembly light energy conversion device. The results show that after 12 h irradiation, the photocatalytic activity of 2.0%WO3-TiO2 with oxygen vacancies in the self-assembly light energy conversion device is higher than that of the ordinary photolysis device, and the amount of oxygen evolution is about 12 and 9 mmol/L respectively in these two devices. After 12 h, the rates of O2 evolution are slow in each device and the photocatalyst almost loses the photoactivity in the ordinary photolysis device. So, compared with the ordinary photocatalytic device, the rate of oxygen evolution and the life time of the catalyst are improved in the self-assembly light energy conversion device.

The degradation of two commercially available dyestuffs (C.I. Reactive Black 5 and C.I. Disperse Orange 25) by ultraviolet radiation (UV), ultrasonic irradiation (US), UV/H2O2 and US/H2O2 processes was investigated in a laboratory-scale batch photoreactor equipped with a 55 W immersed-type low-pressure mercury vapor lamp and a sonoreactor with low frequency (42 kHz) plate type transducer at 170 W of acoustic power. The toxicity was also evaluated in acute toxicity studies using Daphnia magna. Results showed that color removal efficiencies by US and US/H2O2 processes were negligible for both dyes. Almost complete disappearance of Reactive Black 5 (97.9%) in UV/H2O2 process was possible after 5 min of irradiation. The maximum color removal efficiency of Disperse Orange 25 after 10 min of irradiation, however, was only 9.2% and reached a maximum value of 41% after 120 min of irradiation. Pseudo-first order kinetics with respect to dyestuffs concentrations was found to fit all the experimental data. The results clearly showed that both dyes examined were toxic to D. magna and resulted in quite low LC50 values.

Cysts or zoospores of Phytophthora capsici, P. citrophthora and P. nicotianae were suspended in distilled water or in recycled irrigation water collected from commercial nurseries. Propagules, suspended in shallow layers of still water in 60 mm-diameter plastic Petri dishes with lids off, were exposed to various UV doses emitted from either an excimer laser or a mercury vapor lamp. The laser emitted a monochromatic (248 nm, 5 eV/pulse), pulsed UV beam with an intensity of 1 to 2 mJ/cm2/pulse with 20-ns pulse durations and a high peak power of 50 to 100 kW/cm2/pulse. The UV lamp was from a commercial water purifier that emitted broadband (continuous) UV radiation at an intensity of ∼8 mW/cm2. Survival was assessed by culturing aliquots of the treated or non-treated suspensions onto corn meal agar amended with ampicillin (250 ppm) and rifampin (10 ppm), and then counting numbers of developing colonies. The UV dose (as energy per unit area) required to kill propagules was smaller when they were suspended in distilled water than when suspended in recycled nursery water. The reduced kill effectiveness in recycled water appears to be related to UV-absorbing soluble chemicals. Cysts and zoospores were equally susceptible to UV, although the high-peak power pulsed-UV laser source with ultra-short exposure times appeared to have greater kill effectiveness than the conventional Hg-vapor UV lamp. Phytophthora capsici and P. nicotianae isolates were somewhat less sensitive to UV than isolates of P. citrophthora obtained from various hosts and geographical regions. Furthermore, hyphae of Phytophthora spp. were less susceptible to UV than were cysts or zoospores.

A transparent layer photocatalyst having high rubbing resistance was developed. A high temperature burning process cannot be applied to form transparence layer photocatalysts using a low heat-resistant plastic film. We were able to synthesize the transparence layer photocatalyst having high rubbing resistance by irradiation of the hybrid material consisted of urethane acrylic oligomer and titanium lactate using a high pressure mercury lamp. The layer formed through a hybrid reaction of photo-polymerization of urethane acrylic oligomer and the sol-gel reaction of titanium lactate at relatively low temperature. The layer showed high rubbing resistance and high transparency, and titanium include in it dispersed uniformly. Photocatalytic activity was confirmed by detection of radicals using electron spin resonance (ESR) and was also evaluated by measuring bleaching of methylene blue solution.

The novel system of ultraviolet light-emitting diodes (UV LEDs) was studied in water disinfection. Conventional UV lamps, like mercury vapor lamp, consume much energy and are considered to be problem waste after use. UV LEDs are energy efficient and free of toxicants. This study showed the suitability of LEDs in disinfection and provided information of the effect of two emitted wavelengths and different test mediums to Escherichia coli destruction. Common laboratory strain of E. coli (K12) was used and the effects of two emitted wavelengths (269 and 276 nm) were investigated with two photolytic batch reactors both including ten LEDs. The effects of test medium were examined with ultrapure water, nutrient and water, and nutrient and water with humic acids. Efficiency of reactors was almost the same even though the one emitting higher wavelength had doubled optical power compared to the other. Therefore, the effect of wavelength was evident and the radiation emitted at 269 nm was more powerful. Also, the impact of background was studied and noticed to have only slight deteriorating effect. In the 5-min experiment, the bacterial reduction of three to four log colony-forming units (CFU) per cubic centimeter was achieved, in all cases. When turbidity of the test medium was greater, part of the UV radiation was spent on the absorption and reactions with extra substances on liquid. Humic acids can also coat the bacteria reducing the sensitivity of the cells to UV light. The lower wavelength was distinctly more efficient when the optical power is considered, even though the difference of wavelengths was small. The reason presumably is the greater absorption of DNA causing more efficient bacterial breakage. UV LEDs were efficient in E. coli destruction, even if LEDs were considered to have rather low optical power. The effect of wavelengths was noticeable but the test medium did not have much impact. This study found UV LEDs to be an optimal method for bacterial disinfection. The emitted wavelength was found to be an essential factor when using LEDs; thus, care should be taken in selecting the proper LED for maximum disinfection.

Fluorescent characteristics of the photo- and biotransformations of 2-methylphenol, 4-methylphenol and their mixtures in water exposed to uv radiation of various sources and to Penicillium tardum H-2 culture have been studied. The toxicity of these solutions has also been investigated by means of bioluminescent testing. Preliminary exposure of a 4-methylphenol solution (10−3 M) to uv radiation with λ ∼ 308 nm or to the radiation of a mercury lamp inhibited the subsequent microbiological degradation. Efficient decomposition of methylphenol molecules in the mixture was detected when it was exposed to the radiation of a mercury lamp or to 222-nm radiation and then subject to biodecomposition. The irradiation of solutions of 2-methylphenol and 4-methylphenol and their low-concentration mixtures with 308-nm uv radiation or with the radiation of a mercury lamp resulted in detoxication of the solutions. Extreme toxicity was shown by 4-methylphenol solutions on exposure to uv radiation with λ ∼ 222 nm.

We have studied photolysis of a mixture of 2-methylphenol (2-MP) and 4-methylphenol (4-MP) in distilled water and in water containing humic acids. The samples were irradiated under different conditions: by monochromatic light with λ ∼ 222, 283, and 308 nm; by polychromatic light from a mercury lamp in the wavelength region 290–600 nm. We have shown that a mixture of methylphenols is efficiently degraded with irradiation by a KrCl exciplex lamp (λrad ∼ 222 nm). Preliminary treatment of peat before extraction of the humic acids has an effect on the extent of photoconversion of the methylphenols. Regardless of the type of humic acids, their presence in solution inhibits photoconversion. The greatest extent of degradation of the methylphenols in aqueous solutions with humic acid additives is detected for irradiation by a KrCl exciplex lamp or a mercury lamp, but it is lower than the extent of degradation of the mixture of methylphenols in water.

Photocatalytic degradation of dicofol was investigated on TiO2 nano particles (TiO2-NPs) under UV light irradiation. It was shown that dicofol could be completely degraded into inorganic chloride ion under the condition of 0.25 mg/mL TiO2-NPs, 2 h irradiation of 400 W high pressure mercury lamp with a wavelength of 365 nm and air at a rate of 100 mL/min. The effects of the experimental conditions, including the amount of TiO2-NPs, irradiation time and the intensity of light, were studied. The apparent photodegradation rate constant was 0.167/min under the optimal condition. The photocatalytic degradation mechanism of dicofol was also discussed.

The photodegradation of organic dye rhodamine B (RhB) in an aqueous solution was studied using a microwave electrodeless UV lamp (MWUVL). The 185 nm vacuum UV (VUV) intensity of the MWUVL amounted to 12% of the total UV output, about 1.7 times as high as that of the con ventional low-pressure mercury lamp. An acidic condition was preferred for the degradation of RhB. Precipitate was generated during RhB degradation when the initial concentration of RhB solution was above 60 mg · L−1. For 100 mg · L−1 RhB at pH 4.0, the mass of precipitate produced was nearly half of the initial amount of RhB in the solution after irradi ation for 75 min. The corresponding degradation ratio of RhB reached up to 99.4% and COD reduced 77.4%. The photo degradation of RhB is mainly achieved by direct photolysis of RhB by 185 nm and OH radical oxidation.

In this paper, we propose a method to generate gold nanoparticles capable of absorbing near infrared light (NIR) radiation through a photochemical reaction. This approach does not require the use of either surfactants or polymers, reducing the difficulties that may arise in further chemical modifications for the gold nanoparticles. The gold nanoparticles with either triangular or hexagonal shapes were generated using the photo-reduction method, mixing hydrogen tetrachloroaurate with sodium oxalate, a reducing agent, in aqueous solution under illumination of a mercury lamp (λmax = 306 nm) for more than 10 min. The size of the gold nanoparticles varies from 25 to 200 nm, which mainly depends on the duration of light illumination and the concentration of sodium oxalate. Furthermore, we demonstrate that the presence of the gold nanoparticles in aqueous solutions can effectively elevate the temperature of the solutions under irradiation of NIR light (808 nm) within a few minutes. The gold nanoparticles can be potentially used as suitable photothermal agents for hyperthermia.

A novel photocatalytic material (Pt,Cd0.8Zn0.2S)/HLaNb2O7 was fabricated by successive intercalation and exchange reactions. The (Pt,Cd0.8Zn0.2S)/HLaNb2O7 possessed a gallery height less than 0.5 nm and showed a broad absorption with wavelength over 370–500 nm. Using (Pt,Cd0.8Zn0.2S)/HLaNb2O7 as catalyst, the photocatalytic H2 evolution was more than 160 cm3 · h−1 · g−1 in the presence of Na2S as a sacrificial agent under irradiation with wavelength more than 290 nm from a 100-W mercury lamp. Furthermore, the catalyst showed photocatalytic activity even under visible light irradiation.

The purpose of this study was to investigate the influence of several Norrish I (α-cleavage) type photoinitiators and UV dose on the curing behavior and coating performance of UV-curable aliphatic urethane acrylate coatings. UV-curable coatings were cured under a high-pressure mercury lamp. The curing behavior and coating performance of the UV-curable coatings that were cured using 2-hydroxy-2-methyl-1-phenyl-propan-1-one or 1-hydroxy-cyclohexyl-phenyl-ketone were superior to those of the UV-curable coatings cured using bis (2,4,6-trimethylben-zoyl)-phenylphosphine oxide or diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide, when the UV-curable coating was cured in air.

TiO2 gel films were prepared from titanium tetra-n-butoxide chemically modified with benzoylacetoanilide including nitrogen by the sol-gel method. The obtained gel film showed an absorption band, characteristic of the chelate ring, at 325 nm. The absorption band disappeared almost completely with UV-irradiation (2.7 J cm−2) using a high pressure mercury lamp. This indicates that the gel film exhibits photosensitivity. The decomposition rate of the chelate ring was the fastest in the photosensitive TiO2 gel films which we have examined. Using the photosensitivity, fine patterns (about 5 μm) could be fabricated by UV-irradiation through a mask and leaching.

Wavelength dependence was observed in the ultraviolet (UV) irradiation-assisted crystallization of alkoxy-derived ZrO2 thin films. The surface grains of thin films deposited on Si(100) substrates became enlarged by UV irradiation using an ultrahigh-pressure mercury lamp. The crystallinity of thin films deposited on Si(100) substrates was improved by UV irradiation using a low-pressure mercury lamp. The reaction using the ultrahigh-pressure mercury lamp depended on the substrate type.

The aim of this study was to determine whether artificial ultraviolet (UV) light sources are able to imitate properly the photodegradation of wood caused by sunlight. In this study, wood specimens were irradiated with a xenon lamp and a mercury lamp. The xenon light simulated sunlight only in the case of long-term irradiation. The photoinduced yellowing of wood was faster and greater in the case of short-term exposure to xenon light than that caused by sunlight. The number of UV light-generated carbonyl groups absorbing infrared light around 1700 cm−1 showed good correlation with photoinduced yellowing. On the other hand, mercury light did not simulate sunlight. However, the mercury lamp, as a strong UV light emitter, can be applied to determine the valid limits of the Kubelka–Munk (K-M) equation. Our results show that the K-M equation cannot be applied to determine the absorption properties of the sample if the values of the K-M units exceed 50.

SU-8 layers of different thickness that were formed by spinning and soft baking or a casting process with a solvent content of not more than 4% were used for experimental investigation of deep UV lithography using modified radiation of a mercury lamp. The specific absorbance of the SU-8 layers have been measured in dependence on the wavelength to calculate the power of the absorbed radiation as a function of depth in the resist layer. The resist layers which were formed on a photo-mask have been exposed with a variation of exposure dose to study the residual thickness of the resist. There are threshold exposures for the formation of insoluble SU-8 resist layer and for the disappearance of shrinkage of the resist layer, which depends on the size of the irradiated area, on microstructure topology and on the resist thickness for fixed parameters of pre- and post-exposure baking. It has been shown that exact filtration of a low-intensity band of exposure radiation at 334 nm allows to reduce strong diffraction distortion in the upper layer of the resist. Microstructures with an aspect ratio of 25 in a SU-8 resist layer of 1 mm thickness have been obtained using a 100 μm thick SU-8 resist layer as a filter for the UV radiation and with optimal dose of exposure.

The emission characteristics of the low-pressure electrodischarge UV lamp based on a mixture of xenon with iodine vapors have been investigated. The lamp was pumped in a dc longitudinal flow discharge with an interelectrode spacing of 50 cm at an electric power of discharge of 50–250 W. We investigated the volt-ampere characteristics, the plasma radiation spectra, and the dependences of the radiation power and efficiency of the lamp on the discharge electric power and the partial pressure of xenon in the mixture. The total radiation power of the electrodischarge lamp in the 206– 350-nm range reaches 22 W at an efficiency of ≤11%.

The curing kinetics of films produced from compositions based on UV-curable oligourethaneacrylates is investigated using, as a source of radiation, an individual spectral line separated by a monochromator from the radiation of a DRT-400 mercury tubular lamp. It has been established that in the region of spectral sensitivity of the composition, the curing time of the film is inversely proportional to the intensity of volumetric absorption of the radiation-source photons by the initiator at the lower surface of the film under study. Individual contributions of some of the lines to the process of composition curing by using the integral spectrum of the radiation source have been evaluated. The spectral-kinetic results obtained were confirmed when using the compositions under study as protective coatings of optical quartz fibers.

A 650 °C annealed thin film was found to be a single phase of SrBi2Ta2O9 (SBT) and showed the c-axis orientation without ultraviolet irradiation. The crystallinity and crystal orientation of the thin films were improved by ultraviolet irradiation using an ultrahigh-pressure mercury lamp (UHPML) or a low-pressure mercury lamp (LPML) under three conditions. In particular, the crystal orientation of the 650 °C annealed thin films dramatically changed by ultraviolet irradiation using a LPML at room temperature or using an UHPML at 150 °C. The 650 °C annealed SBT thin film prepared by ultraviolet irradiation using an UHPML at 150 °C showed a remanent polarization (Pr) of 4.3 μC/cm2 and a coercive electric field (Ec) of 101 kV/cm at 10 V.

The exploding-wire method, the photochemical method of irradiation with a light flux from a high-pressure mercury lamp, a high-intensity spark discharge, and irradiation by a CO2 laser are used to reduce plutonium hexafluoride and to separate it from uranium hexafluoride. The dependence of the reduction of plutonium hexafluoride on the wire material, the mass of the reduced product, and the amount of input energy is investigated. It is shown that the methods presented for reducing plutonium hexafluoride and separating it from uranium hexafluoride can be used under static and dynamic conditions for preparative purposes and on a large scale.

The emission spectra of four mercury vapor lamps are used to obtain wavelength calibration curves for the double-grating emission monochromator of a spectrofluorimeter. The use of second- and third-order diffraction lines and emission lines from the argon carrier gas provides a rich spectrum, which extends well into the near-infrared spectral region and produces an improved calibration curve. More than 60 emission lines are listed between 250 and 900 nm, which is sufficient to produce an extremely accurate monochromator calibration. Additional second- and third-order lines can be used to even longer wavelengths (>1200 nm). The effectiveness of three scattering surfaces is compared.

The fungicide Flutriafol was mineralised on irradiation of its aqueous solution, in which anatase P25 was suspended, with a medium pressure mercury lamp under an air stream. The half-time of reaction, t1/2, i.e. the time at which the total organic carbon of the solution was halved, decreased in the series of P25 loaded with RuO2>Pt>Ag>MnO2. Heating P25 at 500°C for 3 h reduced t1/2 compared to bare, unheated P25.

Finely patterned transparent, conductive SnO2 thin films have been prepared. UV-light from a high-pressure mercury lamp was irradiated through a mask on the precursor films prepared from SnCl2 with acetyl acetone in the ambient atmosphere, and this irradiation led to the change of solubility of the films in alkaline solution. Patterns with a width of about 3 to 50 μm and thickness of about 0.1 μm were formed with a pitch of about 2 to 20 μm. The resistivity of the films heat-treated at 500°C after UV irradiation was about 1 × 10−2 Ω cm, which was almost the same resisitivity for the films heat-treated at 500°C without UV irradiation.

A high output low-pressure mercury lamp, 400 W L-Hg, was successfully used for the photolytic decomposition of dissolved oganic compounds as the pretreatment for the determination of trace metal ion in aqueous solution by stripping voltammetry. Various amino acids, showing interferences on voltammetric determination of metal ions, can be removed quite easily by intensive UV irradiation at room temperature. Effect of pH, concentration of electrolyte and dissolved oxygen on the efficiency of photolysis are also described. This method uses no additional chemicals such as acids or oxidants and can be carried out in closed clean conditions.

A number of histochemical chromogenic substrates for alkaline phosphatase are commercially available and give reaction products with a range of colours for brightfield examination. Some of these reaction products are also fluorescent, exhibiting a wide excitation range and a broad emission peak. We report here that one of these substrates, Vector Blue III, yields a stable, strongly fluorescent reaction product with an excitation peak around 500 nm and a large Stokes shift to an emission peak at 680 nm. The reaction product can be excited using a mercury lamp with a fluorescein excitation filter or an argon ion laser at 488 nm or 568 nm, and the emission detected using a long-pass filter designed for Cy-5. Thus, a single substrate is suitable for brightfield imaging of tissue sections and high-resolution analysis of subcellular detail, using a confocal laser scanning microscope, in the same specimen.

The cure rate of a high gloss overprint varnish was compared using a standard medium pressure mercury lamp and a high intensity xenon chloride lamp. Samples with equal photoinitiator concentration cured at a much faster rate using the xenon chloride lamp. It was found that the concentration of the photoinitiator could be greatly reduced and still give rapid rates of curing when the xenon chloride lamp with peak output at 308 nm was used.

The optical characteristics of a UV broadband lamp that was excited by a longitudinal glow discharge and operated on Kr—Br2—I2, Xe—Br2—I2, and Kr—Xe—Br2—I2 mixtures are investigated. The interelectrode spacing in the lamp is 10 cm, the inner diameter of a discharge tube being 14 mm. The current-voltage characteristics, the emission spectra of the plasma, and the dependence of the intensity of spectral lines (the amplitude of radiation bands) on the power that was pumped into the plasma based on mixtures of various compositions and pressures, as well as the radiation power in the spectral range from 200 to 390 nm, are studied.

Films of photosensitive polyurethanes based on castor oil and bearing increasing amounts of cinnamoyl groups were obtained and submitted to tensile tests and thermogravimetric analysis. The test samples were cut into strips, with the long axis making angles of 0, 30, 45, 60, 90, 120, 135, and 150° with the suspected direction of anisotropy. In another series of experiments, films were irradiated with a high pressure mercury lamp during different periods of time and again submitted to tensile tests.

The solid-gas phase photoassisted reduction of carbon dioxide (artificial photosynthesis) was performed using ferroelectric lithium niobate and titanium dioxide as photocatalysts. Illumination with a high pressure mercury lamp and visible sunlight showed lithium niobate achieved unexpectedly high conversion of CO2 to products despite the low levels of band gap light available and outperformed titanium dioxide under the conditions used. The high reaction efficiency of lithium niobate is explained due to its strong remnant polarization (70 μC/cm2) thought to allow longer lifetime of photo induced carriers as well as an alternative reaction pathway.

Improvements in selectivity and sensitivity in the analysis of common explosives, like nitrate esters, nitramines and nitroaromatic compounds can be achieved by post-column derivatisation in a two step reaction detector. The first step in derivatisation is the photolysis of the analytes with UV at 254 nm. The photo reactor consists of a crocheted 20 m Tefzel capillary, which is coiled around a low pressure mercury lamp. In second step the nitrite ion generated is subsequently detected by a colourimetric reaction. The azo dye formed can be selectively detected at 540 nm.

1. A low-pressure mercury lamp can be used for the ultraviolet irradiation sterilization of transparent liquid media. 2. The design of a flow ultraviolet irradiation sterilization unit provides for conversion of the bulk flow into a thin layer, thus promoting efficient sterilization by using the full power of the radiation source and achieving good processing rates. 3. The useful power of the sterilization unit provides 163 times the lethal dose of bactericidal radiation for spores of microorganisms in transparent solution. 4. The method of flow ultraviolet irradiation sterilization is economical for treatments requiring the consumption of large volumes of solutions. 5. The optical density of water and aqueous solutions increases proportionally to the dose of irradiation at 254 nm.

Meso-tetra-(p-diazoniumphenyl) porphyrin (TDSPP) can be photolyzed only under anaerobic conditions with a yield of 0.18 during simultaneous irradiation with He-Ne laser light (632.8 nm) and light of the 313 nm line of 0 mercury lamp. The excited singlet state of TDSPP is quenched by externalp-methoxybenzene diazoniumtetra fluoroborate (MeODS) with a rate constant of 9.7 × 109M−1s−1. TDSPP and MeODS interact in the ground state with an equilibrium constant of about 16M−1 and form a fluorescent but photochemically inactive.

H2NiTi4O10/TiO2 intercalated compound was fabricated by successive intercalation reactions of H2NiTi4O10 with n-C6H13NH2/C2H5OH mixed solution and acid TiO2 sol, followed by irradiating with a high-pressure mercury lamp. H2NiTi4O10, a layered perovskite type compound with TiO2-loading, exhibited a high activity for decomposition of methyl orange under UV and visible light irradiation. The experimental results showed that methyl orange was degraded with the decomposition ratio of 59.0 % by using H2NiTi4O10/TiO2 as photocatalyst under visible light ( > 420 nm) irradiation for 24 h. The H2NiTi4O10/TiO2 possessed higher photocatalytic activity than those commercial titania powder (Degussa P-25) which showed the decomposition ratio just only 24% under same condition.

Photooxidation of ethylbenzene with oxygen to give ethylbenzene hydroperoxide has been achieved in a stirred photochemical reactor that was cooled by a water system by irradiation with a 400 W high-pressure mercury lamp and using TiO2 powder and metal coated TiO2. The effects of the amount of copper or silver coated on TiO2 and of the temperature on the rate of oxidation have been investigated. It is suggested that thermal cleavage of the O–O bond and photochemically generated singlet oxygen should be considered as the initiating step in a radical chain mechanism. An optimum loading of 6% Ag or 4–5% Cu was observed for photooxidation of ethylbenzene.