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Reference Module in Materials Science and Materials Engineering || Glass, Self-Cleaning
摘要： In this article, the essential technological and the scientific features of self-cleaning glass coatings based on titanium dioxide have been described. In addition, detailed aspects of the coating process and the functional aspects of the coatings, which provide the dual hydrophilic and photoactive cleaning mechanism, have also been presented.
关键词： Titanium Dioxide,Glass,Hydrophilic,Photocatalytic Activity,Self-Cleaning
更新于2025-09-10 09:29:36
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A crystallization method for preparation of anatase-based glass-ceramic glaze
摘要： Developing a way to prepare effective, durable and high-temperature stable anatase-based photocatalytic ceramic is of great significance. In this work, we report a crystallization method for the preparation of anatase-based glass-ceramic glaze. The raw materials were made into frit and glazed on ceramic bodies. The glazed ceramics were sintered at 1180oC and soaked at 700oC. The effect of soaking temperature on the crystallization process was investigated. The photocatalytic property of the glazed tiles was evaluated by degradation of methyl orange. Experimental results show that after sintering and soaking at 700 oC, nanosized anatase grains crystallize in glaze. The crystallization of anatase nanograins is attributed to the relative high viscosity at crystallization temperature. HF etching makes more anatase grains exposed on the surface. The sample etched for 45 seconds shows the highest photocatalytic activity and the methyl orange is decomposed by about 90% after illumination for 35 h.
关键词： Glass-ceramic glaze,Photocatalytic property,Anatase,Crystallization process
更新于2025-09-10 09:29:36
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On the possibility of the electron-beam welding of quartz glasses by a forevacuum plasma electron source
摘要： The article demonstrates a principle possibility of the electron-beam welding of high-temperature quartz glasses by a plasma electron source operating in the forevacuum range of pressure of 10-50 Pa. We studied the dependence of the composition of the gas atmosphere in the vacuum chamber on the heating temperature of the weld seam. It is shown that the optimal temperature of the weld seam for melting and minimum mass entrainment from the molten pool is 1300 to 1400 0C. We determined the welding regime for cylindrical tubes and rods that provides high seam strength, reaching 90-95% of the original strength of quartz glass.
关键词： forevacuum range of pressure,electron-beam welding,plasma electron source,quartz glass
更新于2025-09-10 09:29:36
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All-optical notch filters for ultra-wideband chaotic communications
摘要： In this paper, a wideband all-optical notch ?lter is proposed using two cascaded modi?ed add-drop resonators from chalcogenide glass (ChG) and GaAsInP-InP waveguide materials. The system consists of ChG main ring and two small side rings called phase modulators made of the GaAsInP-InP materials. The plane waves are fed at the input and add ports, from which the chaotic signal outputs can be generated by the nonlinear e?ect induced into the center ring. The results have been simulated based on the scattering matrix method. Results have shown that the generated chaotic signals can be used for switching and secured communications. An ultra-fast switching time of ～ 2 attoseconds is achieved. Moreover, the chaotic signals can be ?ltered by the stop band ?lters (notch ?lters). The free spectral range (FSR) of two cascaded ChGs is 1494.8 nm. The output wavelength of the notch ?lters is tunable from 748.0–2242.2 nm and 2242.8–3737.0 nm. The band-stop of the notch ?lter is 1494.2 nm. This approach will allow the implementation of the compact, and integrated notch ?lters in an on-chip scale circuit, which is useful for both light ?delity (LiFi) and wireless ?delity (WiFi) applications.
关键词： WiFi,all-optical notch ?lters,chalcogenide glass,GaAsInP-InP,scattering matrix method,ultra-wideband chaotic communications,LiFi
更新于2025-09-10 09:29:36
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Use of a new agricultural product as thermal insulation for solar collector
摘要： Sources of clean energy are becoming increasingly common, and the use of solar thermal energy has also been rising. This paper presents a solar air heater designed with a vegetable material as insulating material, date palm wood, widespread in tropical and saharan countries for use in drying. The study focuses on the comparative thermal performance of this collector and another collectors identical in design, fabrication, and operating under the same conditions, using glass wool as heat insulation. The thermal efficiencies of differents insulators collectors were performed : a) insulator with Petiole Piece, b) insulator with Fibers Piece, c) insulator with Petiole powder, d) insulator with Fibers powder, e) insulator with Petiole + gypsum, f) insulator with Fibers + gypsum insulatin and collector with glass wool insulation were evaluated and graphs were plotted. The final resuls showed that thermal efficiencies of date palm wood (Petiole + gypsum) insulated collector was 37.7 % higher than glass wool insulated collector. The average outlet air temperature of glass wool insulated was 7 % lower than Petiole + gypsum insulated collector. Hence the date palm wood is a good candidate for the development of efficient and safe insulating materials.
关键词： Solar collector,date palm petiole,thermal insulation,gypsum,date palm fibers,glass wool
更新于2025-09-10 09:29:36
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COMPARISON OF OPTICAL METHODS FOR CHARACTERIZATION OF GLASS MOSAIC WEATHERING
摘要： The work presented in this paper is a part of research project supported by Ministry of Culture and devoted to conservation of precious mosaic of "Last Judgement" on St. Vitus Cathedral in Prague. The aim of the project is to enhance external protective polymeric coating on glass tesserae of mosaic and also to develop optical method for assessment of coating’s surface conditions. The paper concentrates on comparison of various methods for surface evaluation assesses their advantages and disadvantages and also discusses their suitability for long term monitoring of coating state, namely re?ectometry, scanning probe microscopy, nanoindentation, white-light interferometry, and scanning electron microscopy. It is found that white-light interferometry and re?ectometry methods are the most suitable ones for monitoring purposes.
关键词： re?ectance,glass mosaic,surface,photometry,roughness
更新于2025-09-10 09:29:36
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Energy dependence of a radiophotoluminescent glass dosimeter for HDR <sup>192</sup> Ir brachytherapy source
摘要： Purpose: We determined correction factors for absorbed dose energy dependence and intrinsic energy dependence for measurements of absorbed dose to water around an 192Ir source using a radiophotoluminescent glass dosimeter (RPLD) calibrated with a 4-MV photon beam. Methods: The ratio of the absorbed dose to the water and the average absorbed dose to RPLD for the 192Ir beam relative to the same ratio in a 4 MV photon beam defines the absorbed dose energy dependence and was determined at distances of 2-10 cm (at intervals of 1 cm) from the 192Ir source in a water phantom using the egs_chamber user code. The RPLD was calibrated to measure absorbed dose to water, Dw, in a 4 MV photon beam using an ionization chamber, which was also used to measure absorbed dose to water, Dw, in a water phantom using the 192Ir source. The detector response (RPL signal per average absorbed dose in the detector) in the 192Ir beam relative to that in the 4 MV photon beam (the relative intrinsic efficiency) was determined experimentally. Finally, the beam quality correction factor was obtained as the quotient between the absorbed dose energy dependence and the relative intrinsic efficiency and corrects for the difference between the beam quality Q0 used at calibration and the beam quality Q used in the measurements. Results: The relative dose ratio of the average absorbed dose to water relative to RPLD ranged from 0.930 to 0.746, and the beam quality correction factor ranged from 0.999 to 0.794 for distances of 2–10 cm from the 192Ir source. The relative detector response to an 192Ir source and the response to a 4-MV photon beam was 0.930, and it did not vary significantly with distance. Conclusions: These results demonstrate that corrections for absorbed dose energy dependence and intrinsic energy dependence are required when using an RPLD to measure with sources different from the reference source providing the primary calibration.
关键词： radiophotoluminescent glass dosimeter,HDR 192Ir brachytherapy source,energy dependence
更新于2025-09-10 09:29:36
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Absorption and luminescence studies of Sm3+ ions activated in distinct phosphate glasses for reddish orange light applications
摘要： In the present work, we report the optical properties of Sm3+ ions doped glasses having chemical compositions (70-x) NH4H2PO4+15Na2O+15M2O + xSm2O3 (where x = 0.5 mol% and M = Li, Mg, Ca, Sr, Ba). Structural details are obtained from XRD, SEM, FTIR, Raman and solid-state 31P NMR spectra. Absorption (UV-NIR), emission and lifetime measurements have been performed and discussed using Judd-Ofelt theory. Various radiative parameters are calculated and discussed. Visible emissions from 4G5/2 excited state have been characterized and the experimental lifetimes of these levels have been compared with those obtained theoretically by using J-O approach. Quantum e?ciencies are reported. The CIE chromaticity co-ordinates of the present glass matrices con?rmed reddish-orange light emission. Hence the prepared samples can be treated as candidates for reddish orange light applications.
关键词： Photoluminescence,Phosphate glass,Absorption,FTIR,Emission cross-section,Solid state 31P NMR
更新于2025-09-10 09:29:36
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Evaluation of the shielding parameters of alkaline earth based phosphate glasses using MCNPX code
摘要： Glass systems of composition 16XO–3Al2O3–6CuO–20Na2O–55P2O5 (where X=Sr, Ca, Mg and Ba mol%) have been investigated to check its potential utilize as gamma ray shielding material. Different shielding quantities namely mass attenuation coefficient (μ/ρ), effective atomic number (Zeff), half value layer (HVL) and mean free path (MFP) have been evaluated using MCNPX code and XCOM program at different photon energies between 0.015-10 MeV. The obtained data revealed good agreement between the μ/ρ values derived from XCOM and MCNPX code (version 2.6.0). It is found that the mass attenuation coefficients of BaO-doped phosphate glass are higher than those of the other alkaline earth elements–doped glasses, whereas MgO possess the lowest values. This indicates that the BaO-doped phosphate glass is the superior gamma radiation attenuator among the studied glass samples. The gamma shielding performance of the glasses under study has been compared to some commercial glasses and different concrete samples in terms of MFP.
关键词： MCNPX,effective atomic number,attenuation coefficients,radiation,Phosphate glass,XCom
更新于2025-09-10 09:29:36
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Crystal structure, microwave dielectric properties and low temperature sintering of (Al0.5Nb0.5)4+ co-substitution for Ti4+ of LiNb0.6Ti0.5O3 ceramics
摘要： The phase composition, microstructure, microwave dielectric properties of (Al0.5Nb0.5)4+ co-substitution for Ti site in LiNb0.6Ti0.5O3 ceramics and the low temperature sintering behaviors of Li2O-B2O3-SiO2 (LBS) glass were systematically discussed. XRD patterns and EDS analysis result confirmed that single phase of Li1.075Nb0.625Ti0.45O3 solid solution was formed in all component. The increase of dielectric constant (εr) is ascribed to the improvement of bulk density. The restricted growth of grain has a negative influence on quality factor (Q×f) value. The τf value could be continuously shifted to near zero as the doping content increases. Great microwave dielectric properties were obtained in LiNb0.6Ti(0.5-x)(Al0.5Nb0.5)xO3 ceramics (x = 0.10) when sintered at 1100℃ for 2 h: εr = 70.34, Q×f = 5144 GHz, τf = 4.8ppm/℃. The sintering aid, LBS glass, can effectively reduce the temperature and remain satisfied microwave performance. Excellent microwave dielectric properties for x = 0.10 were obtained with 1.0 wt. % glass: εr = 70.16, Q×f = 4153 GHz (at 4 GHz), τf = -0.65ppm/℃ when sintered at 925℃ for 2 h.
关键词： LiNb0.6Ti0.5O3 ceramics,low temperature sintering,Li2O-B2O3-SiO2 (LBS) glass,microwave dielectric properties
更新于2025-09-10 09:29:36