Chemical Effects of Light and Photography

This article discusses the chemical and biological effects of light and photography. Light is a form of energy known as electromagnetic radiation, and its expression at wavelengths and the unit of measurement, nanometer, is considered a separate characteristic. It ranges from very short wavelength to long wavelength radiation. Visible (normal / sunlight) light is the band of radiation that our eyes can see. Under the influence of light, the following processes can occur: the attachment of atoms to molecules, dissociation, photochemical reaction, synthesis reaction. This article discusses light and its chemical effects, as well as photography. Keywords: Photosynthesis. Photography, electromagnetic radiation, synthesis, photography, xerography, photography, photochemistry, eosin, erythrosine, methylene film.

Radiation collector systems comparison in Contaminants of Emerging Concern degradation by solar heterogeneous photocatalysis

Wastewater with Contaminants of Emerging Concern (CEC) can be generated from different sources as industry, agriculture and urban and hospital wastes. Heterogeneous Photocatalysis (HP) with TiO2 is one of the Advanced Oxidation Processes (AOPs) most suitable for water treatment with CEC. In this research, three CEC: Safranin T (SF), 2,4-dichlorophenoxyacetic acid (2,4-D) and Sulfacetamide (SAM) degradation was evaluated by solar-HP in a quartz wall reactor. First, 365 nm wavelength radiation was used and the best operating conditions was determined under the high flow and aeration configuration, obtaining a removal rate of 48.05% for SF, 11.64% for 2,4-D and 6.98 for SAM. Then, under these conditions, SF, SAM and 2,4-D degradation with solar lighting was made on 4 radiation collector systems configurations, Flat Plate Collector (FPC), V Collector (VC), Parabolic Collector (PC) and Compound Parabolic Cylinder Collector (CPC) until reaching the same value of accumulated energy (122.77 kJ m− 2) finding that the PC had the best performance in the treatment for the three pollutants. Finally, the Collector Impact Ratio Factor (CIRF) for the pollutants was calculated, achieving until 12 times degradation for SAM.

Turbine Blade Three-Wavelength Radiation Temperature Measurement Method Based on Reflection Error Correction

The turbine blade is a key component in an aeroengine. Currently, measuring the turbine blade radiation temperature always requires obtaining the emissivity of the target surface in advance. However, changes in the emissivity and the reflected ambient radiation cause large errors in measurement results. In this paper, a three-wavelength radiation temperature measurement method was developed, without known emissivity, for reflection correction. Firstly, a three-dimensional dynamic reflection model of the turbine blade was established to describe the ambient radiation of the target blade based on the real surface of the engine turbine blade. Secondly, based on the reflection correction model, a three-wavelength radiation temperature measurement algorithm, independent of surface emissivity, was proposed to improve the measurement accuracy of the turbine blade radiation temperature in the engine. Finally, an experimental platform was built to verify the temperature measurement method. Compared with three conventional colorimetric methods, this method achieved an improved performance on blade temperature measurement, demonstrating a decline in the maximum error from 6.09% to 2.13% and in the average error from 2.82% to 1.20%. The proposed method would benefit the accuracy in the high-temperature measurement of turbine blades.

Characteristic of TiO2-SiO2 Nanofluid With Water/Ethylene Glycol Mixture for Solar Application

Solar energy is a sustainable energy supply technology due to the renewable nature of solar radiation and the ability of solar energy conversion systems to generate greenhouse gas-free heat and electricity during their lifetime. In this study, an experimental investigation was conducted to explore the effect of hybrid nanofluids on heat transfer for solar application. An experiment was conducted for hybrid nanofluid concentrations starting from 0.3, 0.5, 0.7 and 1.0%. Each setup was exposed to short wavelength radiation under a solar simulator with 300, 500 and 700 W/m2 for 30 minutes, of which 15 minutes is the heating period and the next 15 minutes is for cooling. For solar radiation of 300 W/m2 within 15 minutes of charging process are 51.9 °C, 52.8 °C, 53.4 °C and 54.2 °C for concentration of nanofluids 0.3, 0.5, 0.7 and 1.0% respectively. The results for solar radiation of 500 and 700 W/m2 within 15 minutes almost the same pattern which is increasing during the charging process. It can be concluded that the higher concentrations of nanofluid give ample time to the test tube to transfer the heat and thus increased its temperature during the charging process.

Особенности излучательных свойств квантово-размерных частиц узкозонных полупроводников

For colloidal quantum-size particles (QP) of narrow-gap semiconductors, in contrast to quantum dots of wide-gap CdSe, in QP-PbS there take place an anomalous temperature dependence of the photoluminescence intensity. Also, in the planar microstructure containing QP-InSb, long-wavelength radiation (more than 3 µm) and photoconductivity (over 20 µm) was observed. Under certain conditions, the radiation intensity and photoconductivity demonstrate a resonance maximum. The effects were explained in the model of a one-dimensional quantum oscillator, which energy substantially depends on the effective mass of its quasi-free electron. This leads to competition between the manifestations of long-wave radiation and photoluminescence, and hence, to the anomalous temperature dependence of photoluminescence. It is assumed that QP-InSb in a planar microstructure can be sources and receivers of terahertz radiation, which properties depend on the crystal structure of quantum-sized particles determined by the parameters of their synthesis.

Treatment of palpebral melanocytic nevi with a dual-wavelengths copper vapor laser

Acquired melanocytic nevi in aesthetically significant areas, especially palpebral nevi (PN), are becoming a frequent reason for patients to seek dermatologists. Surgical methods for removal of PN are reported to be associated with the risk of such side effects as scars and loss of eyelashes. Aim of the study. To evaluate the efficacy of the removal of PN on the eyelid area with dual-wavelength radiation of a copper vapor laser (CVL). Patients and methods. Laser removal of medium and large-sized PN (up to 10 mm) was performed in three fair-skin female patients. The procedures were carried out at an average CVL radiation power of 0.60.8 W, at a 3:2 ratio of radiation powers at wavelengths of 511 nm and 578 nm, exposure duration 0.3 s, light spot diameter 1 mm. The treatment was carried out during one session. Results. Removal of PN with dual-wavelength CVL radiation allowed achieving a significant lightening and reduction of the involved area, without scars. The skin healing after the procedure lasted 2 weeks. Conclusion. The high efficacy of the PN removing in the eyelid area using the dual-wavelength CVL radiation allows the introduction of this approach into dermatologists and cosmetologists clinical practice.

Treatment of palpebral melanocytic nevi with a dual-wavelengths copper vapor laser

Acquired melanocytic nevi in aesthetically significant areas, especially palpebral nevi (PN), are becoming a frequent reason for patients to seek dermatologists. Surgical methods for removal of PN are reported to be associated with the risk of such side effects as scars and loss of eyelashes. Aim of the study. To evaluate the efficacy of the removal of PN on the eyelid area with dual-wavelength radiation of a copper vapor laser (CVL). Patients and methods. Laser removal of medium and large-sized PN (up to 10 mm) was performed in three fair-skin female patients. The procedures were carried out at an average CVL radiation power of 0.60.8 W, at a 3:2 ratio of radiation powers at wavelengths of 511 nm and 578 nm, exposure duration 0.3 s, light spot diameter 1 mm. The treatment was carried out during one session. Results. Removal of PN with dual-wavelength CVL radiation allowed achieving a significant lightening and reduction of the involved area, without scars. The skin healing after the procedure lasted 2 weeks. Conclusion. The high efficacy of the PN removing in the eyelid area using the dual-wavelength CVL radiation allows the introduction of this approach into dermatologists and cosmetologists clinical practice.

Manipulation of landing behaviour of two whitefly species by reflective foils

Whiteflies are major pests on several vegetable and ornamental crops. Landing behaviour is strongly influenced by wavelength (nm) of reflected light from ground and surrounding vegetation. This paper deals with manipulation of whitefly landing behaviour in semi-field greenhouse experiments using background foils, either white foils with high reflection of short wavelength radiation or green foils reducing contrast between target plants and background (soil). The reactions of two different whitefly species were compared to detect possible differences between specialist (Aleyrodes proletella) and generalist (Trialeurodes vaporariorum) species. Dual-choice experiments were performed in a greenhouse using ice-lettuce, Lactuca sativa var. capitata (T. vaporariorum) and broccoli, brassica oleracera var. Italica P (A. proletella) as model plants. The results show strong impact of the white reflective foil in controlling landing behaviour of both species, whereas the effect of the contrast-minimising foil was much lower. Light influence was stronger on generalist than on specialist species. Mechanisms behind these effects and opportunities for inclusion in an integrated pest management strategy are discussed.