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Rustam S. Zakirullin - One of the best experts on this subject based on the ideXlab platform.

  • Optical filter for smart windows with angle-selective Light Transmission
    Journal of Optical Technology, 2019
    Co-Authors: Rustam S. Zakirullin
    Abstract:

    A grating optical filter for a smart window is presented, which provides dynamic control of the dayLight and solar energy indoors throughout the year without human intervention and without the use of dayLight-redirecting devices. Thin-layer gratings of alternating directionally transmissive and nontransmissive parallel bands on both surfaces of a window are arranged at an angle to the horizontal, taking into account the Sun’s trajectory relative to the window. The methods for calculating the optimal geometric parameters and angular characteristics of the filter for minimizing the Light Transmission for a specific date and time of day at a given latitude and longitude of the building and the azimuth of the window are described. A numerical simulation of the Light Transmission is performed, and the results are confirmed experimentally.

  • An optical filter with angular selectivity of the Light Transmission
    Proceedings of SPIE, 2015
    Co-Authors: Rustam S. Zakirullin
    Abstract:

    Features of the application of a novel optical filter with angular selectivity of the Light Transmission to architectural glazing are considered. The filter consists of a sheet transparent substrate with thin-film grating layers on both surfaces. The gratings formed by directionally transmissive strips, alternating with absorptive, reflective, or scattering strips. Their relative position on the input and output surfaces provides angular selectivity of the directional Light Transmission – as the incidence angle changes, the proportion of radiation that passes through both gratings of the filter also changes. Chromogenic materials currently used in the laminated smart windows, providing control over the intensity and spectrum of the transmitted solar radiation, cannot achieve the selective regulation on the ranges of incidence angles. Such a regulation requires the use of additional dayLight-redirecting devices, especially blinds, to dynamically adapt to the position of the sun. The grating optical filter provides angular selectivity of the Light Transmission of a window without such devices. The features of using this filter in the single and double glazed windows are described. A graphic analytical calculation method is proposed for estimating the effect of geometrical and optical parameters of the filter on the angular characteristics of the Light Transmission. An algorithm to optimize filtering solar radiation taking into account the geographical coordinates of terrain, time of day and year and the orientation of the window to the cardinal is set. An algorithm to calculating geometrical parameters of the filter with pre-specified characteristics of the Light Transmission is obtained.

S. D. Khizhnyak - One of the best experts on this subject based on the ideXlab platform.

  • Temperature-induced variation of the Light Transmission in a polymeric optical fiber
    Polymer Science Series B, 1996
    Co-Authors: S. D. Khizhnyak, P. M. Pakhomov, A. I. Zubkov
    Abstract:

    The effect of elevated temperatures (20-100°C) on the Light Transmission in a PMMA based optical fiber was studied by the Light absorption and scattering measurements in the IR and visible range. Heating of the fiber to 70°C produced no marked changes in the Light Transmission. The further increase in the temperature was accompanied by a marked growth in the optical losses due to the absorption and scattering of Light. The losses are mostly caused by the glass transition in PMMA, which leads to distortions of the Lightguide geometry and degradation of the polymer.

  • The effect of crazing on Light Transmission in polymeric optical fibers
    Polymer science, 1994
    Co-Authors: P. M. Pakhomov, A. I. Zubkov, S. D. Khizhnyak
    Abstract:

    The effect of crazing induced by bending and tensile drawing on Light Transmission in polymeric optical fibers with a PMMA core was studied by optical spectroscopy, microscopy, and Light scattering. Depending on bending curvature and static tensile stress, reversible and irreversible changes in Light Transmission were observed. In both cases, irreversible changes were related to the appearance in PMMA of crazes ∼100 nm in dimension, which scattered the Light. The magnitude of irreversible changes was shown to be proporbonal to the density of crazes nucleated upon deformation of the Light guides. The reversible changes were accounted for by violation of the law of total internal reflection on bending the Light guide as well as by the appearance of the self-healed crazes on the tensile drawing of the samples

Junji Tagami - One of the best experts on this subject based on the ideXlab platform.

  • Light Transmission characteristics of dentine and resin composites with different thickness.
    Journal of Dentistry, 2012
    Co-Authors: Masatoshi Nakajima, Ayako Arimoto, Taweesak Prasansuttiporn, Ornnicha Thanatvarakorn, Richard M. Foxton, Junji Tagami
    Abstract:

    Abstract Objective The purpose of this study was to evaluate the Light Transmission characteristics of dentine and resin composites with different thickness. Methods Disks of bovine dentine and three resin composites (Estelite Σ, Beautifil II and Clearfil Majesty) of OA2 shade were prepared with various thicknesses (0.5, 1.0 and 2.0 mm). Using a goniophotometer, the distribution graphs of the Light Transmission intensity of each specimen were obtained, and diffusion factor (DF) as an indicator for a diffuse Transmission property and peak-gain (G0) for a straight-line Transmission property were calculated. Their colors were measured on black and white backings using a reflection spectrophotometer to calculate translucency parameter (TP). The data of each value (G0, DF and TP) were analyzed by two-way ANOVA and Dunnett's T3 for post hoc test ( p  = 0.05). Regression analyses were used to determine the correlation between G0, DF, TP values and the thickness. Results Regardless of the thickness, dentine had lower TP values than the resin composites. 0.5 mm-thick specimens of dentine and resin composite produced various G0 and DF values, with dentine exhibiting significantly lower G0 and higher DF than the resin composites ( p R 2  = 0.962, p R 2  = 0.891, p Conclusions Dentine had different Light Transmission characteristics from resin composite, depending on the thickness. Clinical significance Dentine has different Light Transmission characteristics (straight-line and diffusion) from resin composite, depending on thickness. Resin composite restoration might be different to accurately reproduce Light Transmission characteristics of dentine substrate.

  • Light Transmission characteristics of dentine and resin composites with different thickness.
    Journal of dentistry, 2012
    Co-Authors: Masatoshi Nakajima, Ayako Arimoto, Taweesak Prasansuttiporn, Ornnicha Thanatvarakorn, Richard M. Foxton, Junji Tagami
    Abstract:

    The purpose of this study was to evaluate the Light Transmission characteristics of dentine and resin composites with different thickness. Disks of bovine dentine and three resin composites (Estelite Σ, Beautifil II and Clearfil Majesty) of OA2 shade were prepared with various thicknesses (0.5, 1.0 and 2.0mm). Using a goniophotometer, the distribution graphs of the Light Transmission intensity of each specimen were obtained, and diffusion factor (DF) as an indicator for a diffuse Transmission property and peak-gain (G0) for a straight-line Transmission property were calculated. Their colors were measured on black and white backings using a reflection spectrophotometer to calculate translucency parameter (TP). The data of each value (G0, DF and TP) were analyzed by two-way ANOVA and Dunnett's T3 for post hoc test (p=0.05). Regression analyses were used to determine the correlation between G0, DF, TP values and the thickness. Regardless of the thickness, dentine had lower TP values than the resin composites. 0.5 mm-thick specimens of dentine and resin composite produced various G0 and DF values, with dentine exhibiting significantly lower G0 and higher DF than the resin composites (p<0.05), whereas with the 1.0 and 2.0mm-thick specimens, they were closely aligned. For dentine, G0 and DF increased in inverse proportion to the thickness (G0: R(2)=0.962, p<0.001; DF: R(2)=0.891, p<0.001). Dentine had different Light Transmission characteristics from resin composite, depending on the thickness. Dentine has different Light Transmission characteristics (straight-line and diffusion) from resin composite, depending on thickness. Resin composite restoration might be different to accurately reproduce Light Transmission characteristics of dentine substrate. Copyright © 2012 Elsevier Ltd. All rights reserved.

A. I. Zubkov - One of the best experts on this subject based on the ideXlab platform.

  • Temperature-induced variation of the Light Transmission in a polymeric optical fiber
    Polymer Science Series B, 1996
    Co-Authors: S. D. Khizhnyak, P. M. Pakhomov, A. I. Zubkov
    Abstract:

    The effect of elevated temperatures (20-100°C) on the Light Transmission in a PMMA based optical fiber was studied by the Light absorption and scattering measurements in the IR and visible range. Heating of the fiber to 70°C produced no marked changes in the Light Transmission. The further increase in the temperature was accompanied by a marked growth in the optical losses due to the absorption and scattering of Light. The losses are mostly caused by the glass transition in PMMA, which leads to distortions of the Lightguide geometry and degradation of the polymer.

  • The effect of crazing on Light Transmission in polymeric optical fibers
    Polymer science, 1994
    Co-Authors: P. M. Pakhomov, A. I. Zubkov, S. D. Khizhnyak
    Abstract:

    The effect of crazing induced by bending and tensile drawing on Light Transmission in polymeric optical fibers with a PMMA core was studied by optical spectroscopy, microscopy, and Light scattering. Depending on bending curvature and static tensile stress, reversible and irreversible changes in Light Transmission were observed. In both cases, irreversible changes were related to the appearance in PMMA of crazes ∼100 nm in dimension, which scattered the Light. The magnitude of irreversible changes was shown to be proporbonal to the density of crazes nucleated upon deformation of the Light guides. The reversible changes were accounted for by violation of the law of total internal reflection on bending the Light guide as well as by the appearance of the self-healed crazes on the tensile drawing of the samples

Ann M. Anderson - One of the best experts on this subject based on the ideXlab platform.

  • A Light Transmission Based Liquid Crystal Thermography System
    Journal of Heat Transfer-transactions of The Asme, 2008
    Co-Authors: Timothy B. Roth, Ann M. Anderson
    Abstract:

    This paper presents results from a study aimed at developing a novel thermochromic liquid crystal (TLC) temperature measurement system that uses Light Transmission instead of Light reflection to measure surface temperature fields. In previous work, we reported on the effect of temperature on Light Transmission through TLCs as measured with a spectrophotometer [Roth, T. B., and Anderson, A. M., 2005, “Light Transmission Characteristics of Thermochromic Liquid Crystals ,” Proceedings of IMECE2005, Orlando, FL, Paper No. IMECE2005-81812;Roth, T. B., and Anderson, A. M., 2007, “The Effects of Film Thickness, Light Polarization and Light Intensity on the Light Transmission Characteristics of Thermochromic Liquid Crystals ,” ASME J. Heat Transfer, 129(3), pp. 372–378]. Here we report on results obtained using a charge coupled device (CCD) camera and polychromatic Light setup that is similar to the type of equipment used in TLC reflection thermography. We tested three different Light sources, a white electroluminescent Light, a green electroluminescent Light, and a halogen fiber optic Light, using both direct and remote Lighting techniques. We found that the green signal (as detected by the CCD camera) of the green electroluminescent Light makes the best temperature sensor, because under remote Lighting conditions it showed a 500% linear signal increase as the temperature of the R25C10W TLCs was raised from 30°to48°C. We further found that the angle of the CCD camera relative to the Light did not significantly affect the results for angles up to 10deg for remote Lighting and 15deg for direct Lighting. The effect of Light intensity variation was not significant for intensities up to 40% of the original level when normalized on the intensity at 19°C (a temperature outside the active range of the TLCs). The use of Light Transmission results in a larger range of temperature over which the TLCs can be calibrated and offers opportunities for more uniform Lighting conditions, which may help overcome some of the problems associated with Light reflection.

  • Liquid Crystal Thermography Using Light Transmission
    9th AIAA ASME Joint Thermophysics and Heat Transfer Conference, 2006
    Co-Authors: Timothy B. Roth, Ann M. Anderson
    Abstract:

    This paper presents results from our study to develop a novel thermochromic liquid crystal (TLC) temperature measurement system that uses Light Transmission instead of Light reflection to measure surface temperature fields. In previous work, we showed that the effect of temperature on Light Transmission through TLCs could be measured with a spectrophotometer. Here we report on results obtained using a CCD camera and polychromatic Light source. We tested three different Light sources: a white electroluminescent Light, a green electroluminescent Light and a halogen fiber optic Light. We found that the green signal (as detected by the CCD camera) of the green electroluminescent Light makes the best temperature sensor, because it showed a 500% linear signal increase as the temperature of the R25C10W TLCs was raised from 30 to 48 o C. Focusing on the green signal from the green Light, we further found that the angle of the CCD camera relative to the Light, did not significantly affect the results for angles up to 10 degrees. The effect of Light intensity was also not significant for intensities up to 40% of the original level, when normalized on the intensity at 24 o C (a temperature outside the active range of the TLCs). The use of Light Transmission results in a larger range of temperature over which the TLCs can be calibrated and offers opportunities for more uniform Lighting conditions which may help to overcome some of the problems associated with Light reflection.

  • Light Transmission Characteristics of Thermochromic Liquid Crystals
    Heat Transfer Part A, 2005
    Co-Authors: Timothy B. Roth, Ann M. Anderson
    Abstract:

    This paper presents the results of a study to develop a novel thermochromic liquid crystal (TLC) temperature measurement system that uses Light Transmission instead of Light reflection. We used Imagetherm 25C10W sprayable TLCs. The TLCs were painted on a clear surface and placed in a spectrometer. The amount of Light transmitted at monochromatic wavelengths from 400 to 700 nm was measured for temperatures from 25–55 C under conditions of non-polarized, linearly polarized and cross polarized Light. The Transmission spectra exhibit a distinct “s-like” shape when the TLCs are in their active range. We detect significant changes in the Transmission spectra for temperatures from 27 to 48 C (whereas in reflection the TLCs are useful over a significantly smaller range). We have analyzed the spectrometer data in a number of ways including (a) total amount of Light transmitted (b) amount of red, green and blue Light transmitted, and (c) spectral curve characteristics (peak Transmission, inflection wavelength and wavelength for peak Transmission) all as a function of temperature. There is a linear relationship between temperature and all of these variables which we believe can be exploited in the development of a CCD camera based Light Transmission system. We also investigated the effects of temperature overheat on the Transmission spectra. Overheating the TLCs increases the amount of Light Transmission.Copyright © 2005 by ASME