Papers by Keyword: Light Transmission

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Authors: M. Fathi, M. Abderrezek, M. Friedrich, K. Tabani
Abstract: In this paper, we propose and experiment the application of self-cleaning Nano coating on solar panels. We have measured an important increase of water droplet contact angle on a Nano coated surface. We found beneficial effects on light transmittance and Open Circuit Voltage (Voc) for the photovoltaic modules. Experimentally, we have shown a higher Transmission coefficient (T) in case of treated glass. In addition, from Thermal Camera analysis, we have shown that the Nano coated Photovoltaic module became cooler and cleaner comparatively to untreated module.
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Authors: Immanuel Schäfer
Abstract: Fenestraria aurantiaca (also known as window plant) is a succulent with specialized adaptations to deal with heat, light and aridity. Fenestraria aurantiaca (F. a.) grows with most of its body under the sand. Just the top, with a light transparent surface – the window – on it, protrudes from the surface hence giving explanation to the plants name. Experiments with light, and detailed microscopy studies show the physical, biological and chemical capabilities of F. a. It was found that the window works as a lens, light from a 90 ° angle is directed into the plant. Thereby the window filters the light. Up to 90 % of the visible light is blocked; with rising wavelength the window gets more transparent until the near infrared light (1000 nm) where the transparency declines rapidly. But the parenchyma is up 90 % transparent. Based on those results the principles of the plant were defined, which are used for abstractions. Generally F.a. has four principles: light handling, surface cleaning, heat avoidance and water storing. Improvements founded on the inspiration of the window plant seem to be possible in photovoltaic systems, which have problems with overheating and also light concentration. An example solution called “buried solar cells” is presented. Another working field is the screen of mobile devices, where the clarity and readability suffers from direct sunlight. With the help from the methods displayed by F.a., there is an energy saving solution explained.
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Authors: Lenka Janečková, Stanislav Darula, Daniela Bošová
Abstract: This paper discusses tube transmission efficiency of two straight hollow light guides. Two samples with diameter of 530 mm and length 1170 mm were investigated under the artificial sky in the laboratory at ICA SAS in Bratislava. The entering luminous flux was calculated from measured illuminance in the point located on the top of light guide. Below the bottom of the light guide was located a set of measuring points on the special construction in the shape of a cross. In these points, one by one, the elementary illuminances were measured and the luminous fluxes leaving the light guide were calculated. Paper presents methodology for laboratory light transmission measurements and discusses effects of two various coating materials on light transmission efficiency of hollow light guides.
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Authors: Tie Cheng Lu, Xue Jun Wang, Bing Xun Cheng, Qiang Hu, Shao Bo Dun
Abstract: In this paper, transparent ceramics Mn:MgAl2O4, which are potentially applicable in visibleband laser field, were prepared and their light transmission and photoluminescence properties were investigated. In experiment, Mn:MgAl2O4 powders with two kinds of doping concentrations of 0.5 and 1.0 at% were synthesized through a high-temperature calcination method with NH4Al(SO4)2·12H2O and MgSO4·7H2O as raw materials, and with MnSO4·H2O as dopant. Transparent ceramics Mn:MgAl2O4 were prepared through vacuum hot-pressing sintering at 1750oC for 1 h, and subsequent vacuumannealing at 1700oC for 2 h. The samples were measured by means of light transmission and photoluminescence. The results show that transparent ceramics Mn:MgAl2O4 can be prepared by a low-cost powder technique and vacuum hot-pressing sintering. Two channels of visible-band luminescence, one peak around 520nm and one wideband centered at 650nm, respectively, can be shown. The intensity of their luminescence increases with increasing doping concentration. Obviously, it possesses a potential application in the field of visible-band solid tunable laser material with high doping concentration.
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Authors: Jian Qi Qi, Tie Cheng Lu, Xiang Hui Chang, Mu Yun Lei, Cun Xin Huang
Abstract: MgAl2O4 transparent nano-ceramic samples have been successfully prepared by ultrahighpressure- sintering method. The ultrafine MgAl2O4 nano-powder was obtained by high-temperaturecalcination method. The samples were sintered at relatively low temperatures (540, 620 and 700°C) under ultrahigh pressures (3, 3.7 and 5GPa) with a six-pressure-source and hexahedral anvil machine that is customarily used for diamond synthesis. The average grain sizes of the prepared samples range from 50 to 75nm. All of the samples sintered under different conditions are transparent. The sample sintered at 620°C under 3.7GPa has the highest density as well as the highest light transmittance (about 50%) at 1300 ~ 1700 nm. The results showed that the ultrahigh-pressure-sintered samples exhibit unique light transmission properties though their densities are not much higher (<97%), compared to the samples, of which densities are higher (>99.5%), obtained by conventional hot-pressing or hot isotopic pressing sintering methods. The light transmittance, its affecting factors and transparent mechanism of the MgAl2O4 samples have been discussed.
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Authors: Kristián Kondáš, Stanislav Darula
Abstract: Windows are one of the most important parts of the building façade. Their main function is to ensure sufficient illumination of interiors and contact with outdoor environment, either directly or indirectly. The optical properties of the glazed part of these envelop apertures have significant influence on a lot of requirements, which have to be satisfied at the same time. The daylight distribution on the working plane is most affected by the glazing system’s light transmission. This study offers a simple method, how to find the appropriate value of the glazing system’s light transmission in relation to the Daylight Factor, in order to ensure the required daylight distribution in interior.
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