Готові списки джерел за темами / Coefficient of transmittance

Добірка наукової літератури з теми "Coefficient of transmittance"

Автор: Grafiati
Опубліковано: 30 травня 2022
Оновлено: 31 травня 2022

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Статті в журналах з теми "Coefficient of transmittance"

1

Hendricks, T. J., and J. R. Howell. "New Radiative Analysis Approach for Reticulated Porous Ceramics Using Discrete Ordinates Method." Journal of Heat Transfer 118, no. 4 (November 1, 1996): 911–17. http://dx.doi.org/10.1115/1.2822588.

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Анотація:
A novel radiative modeling technique using discrete ordinates has been developed for reticulated porous ceramics (RPCs) from experimental measurements of transmittance and reflectance on small samples of partially stabilized zirconium oxide (PS ZrO2) and oxide-bonded silicon carbide (OB SiC). The new technique defines and quantifies the direct transmittance fraction, fdt, of a reticulated porous ceramic, demonstrates how it redefines the extinction process, and creates a new effective extinction coefficient, Kλ,eff. This ultimately produces a modified form of the radiative transfer equation (RTE) and an innovative discrete ordinates formulation to solve the RTE unique to RPCs. The direct transmittance modeling approach has been compared to a more conventional homogeneous modeling approach, in which the direct transmittance effects are essentially ignored and the RPC is treated as a homogeneous lump of material. The two modeling approaches yield identical results in predicting small test sample reflectances and transmittances. The direct transmittance technique does demonstrate explicitly, through a unique relationship between absorption coefficients in the two modeling approaches, the importance of scattering processes in enhancing the absorption mechanism in RPCs. It can also be an important secondary modeling technique that imposes additional parameter constraints in an inverse analysis to help refine derived radiative coefficients.
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2

Kanayama, K., and H. Baba. "Transmittance of Distilled Water and Sodium-Chloride-Water Solutions." Journal of Solar Energy Engineering 110, no. 2 (May 1, 1988): 113–19. http://dx.doi.org/10.1115/1.3268240.

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The spectral transmittance of pure water and salt water solutions of various concentrations, which are important for the thermal calculation of a solar pond, is measured experimentally for specimen thickness of 1 to 100 mm by means of an autorecording spectro-radiometer inside an air-conditioned room. On the basis of the measured spectral transmittance, the total transmittance of pure and salty waters to 3 m of water depth is calculated as a ratio of the total radiation energy over all wavelengths arriving at any depth from the water surface of the solar pond to the solar radiation incident upon the water surface with various air masses. According to Nielsens’ four-partition method, the effective absorption coefficient is calculated for each wavelength band. Lastly, the transmission properties obtained for pure water, i.e., spectral and total transmittances, absorption wavelength band, and effective absorption coefficient, are compared with past results, and those for salty water with various concentrations are compiled as basic data for the use of solar energy by a solar pond.
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3

Hayashi, Takahiro, Takayuki Kobayashi, and Jun Takahashi. "Quantification of the void content of composite materials using soft X-ray transmittance." Journal of Thermoplastic Composite Materials 30, no. 11 (April 24, 2016): 1522–40. http://dx.doi.org/10.1177/0892705716644670.

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Анотація:
Carbon fiber reinforced thermoplastics (CFRTPs) have high potential in high-cycle (1 min) molding as a weight-reducing material for the mass production of automobile components. However, residual voids in CFRTPs lead to diminished and unstable mechanical properties; therefore, the effective quantification of the void content in CFRTP products is necessary for developing an affordable system for mass production. In a previous study, we demonstrated that the X-ray attenuation coefficient decreases with increasing void content; thus, measurements of X-ray attenuation coefficients can be used to estimate the void contents of CFRTPs. In this study, we first investigated in detail the soft X-ray attenuation coefficients of completely impregnated composite materials with three different thicknesses; we observed that the attenuation coefficients decreased with increasing composite thickness, even though they should be independent of the thickness according to the Beer–Lambert law. We next demonstrated that although no correlation exists between the X-ray transmittance and the apparent attenuation coefficient of six composites with various void contents, the true attenuation coefficient modified to account for void content exhibits a good linear relationship with the X-ray transmittance, same as fully impregnated composites. Using the approximation line between the X-ray transmittance and the modified attenuation coefficient of CFRTP, we estimated the void content on the basis of the difference between the apparent and true X-ray attenuation coefficients. The average difference in void content determined by conventional hydrostatic weighing and that determined by the proposed X-ray transmittance method was 0.43%. We therefore concluded that the void content of CFRTPs of any thickness can be estimated nondestructively using soft X-rays.
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4

Peris-Martínez, Cristina, Mari Carmen García-Domene, Mariola Penadés, María Josefa Luque, Ester Fernández-López, and José María Artigas. "Spectral Transmission of the Human Corneal Layers." Journal of Clinical Medicine 10, no. 19 (September 29, 2021): 4490. http://dx.doi.org/10.3390/jcm10194490.

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Анотація:
We have assessed the spectral transmittance of the different layers of the human cornea in the ultraviolet (UV), visible, and near-infrared (IR) spectral ranges. Seventy-four corneal sample donors were included in the study. Firstly, the corneal transmittance was measured using a spectrophotometer. Then, all samples were fixed for histopathological analysis, which allowed us to measure the thickness of each corneal layer. Finally, the absorption coefficients of the corneal layers were computed by a linear model reproducing total transmittance. The results show that corneal transmission was almost in unity at the visible and IR ranges but not at the UV range, in which the layer with higher transmission is Descemet’s membrane, whereas the stroma showed the lowest transmittance. Regarding the absorption coefficient, the most absorptive tissue was Bowman’s layer, followed by the endothelium. Variations on transmittance due to changes in the stroma, Bowman’s layer, or Descemet layer were simulated, and important transmission increases were found due to stroma and Bowman changes. To conclude, we have developed a method to measure the transmittance and thickness for each corneal layer. All corneal layers absorb UV light to a greater or lesser extent. The absorption coefficient is higher for Bowman’s layer, while the stroma is the layer with the lowest transmittance due to its thickness. Variations in stroma thickness or changes in the corneal tissue of Bowman’s layer or the endothelium layer due to some pathologies or surgeries could affect, to a greater or lesser degree, the total transmission of the cornea. Thus, obtaining accurate absorption coefficients for different layers would help us to predict and compensate these changes.
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5

Qi, Hanbing, Lu Yang, Xinhao Hu, Dong Li, Qiushi Wang, and Guozhong Wu. "Optical Properties of Oilfield Wastewater and its Application in Measuring Oil Content." Applied Spectroscopy 72, no. 8 (June 18, 2018): 1252–57. http://dx.doi.org/10.1177/0003702818767405.

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Optical properties of oilfield wastewater play an important role in the on-line measurement of oil content. As an important parameter of optical properties, absorption coefficient is usually obtained by indirectly modeling transmittance spectra. In this work, transmittance spectra of oilfield wastewater in the wavelength range of 190–900 nm at normal incidence were measured by TU-1900 double beam ultraviolet visible spectrophotometer. The absorption coefficient of oilfield wastewater was obtained by a double thickness method, and the relationship between the oil content in oilfield wastewater and its absorption coefficient was studied. The results show that the transmittance spectra of oilfield wastewater decrease with the increase of oil content. The oil content of oilfield wastewater is found to correlate negatively with its transmittance. The oil content of oilfield wastewater and its absorption coefficient have a good fitting effect at 234 nm, and the fitting error of three order polynomial fitting is minimal, with a range of 0.02–5.39%, and the fitting accuracy is 0.9940.
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6

Pereyra, Pedro. "Photonic Transmittance in Metallic and Left Handed Superlattices." Photonics 7, no. 2 (April 18, 2020): 29. http://dx.doi.org/10.3390/photonics7020029.

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Анотація:
We study the transmission of electromagnetic waves through layered structures of metallic and left-handed media. Resonant band structures of transmission coefficients are obtained as functions of the incidence angle, the geometric parameters, and the number of unit cells of the superlattices. The theory of finite periodic systems that we use is free of assumptions, the finiteness of the periodic system being an essential condition. We rederive the correct recurrence relation of the Chebyshev polynomials that carry the physical information of the coherent coupling of plasmon modes and interface plasmons and surface plasmons, responsible for the photonic bands and the resonant structure of the surface plasmon polaritons. Unlike the dispersion relations of infinite periodic systems, which at best predict the bandwidths, we show that the dispersion relation of this theory predicts not only the bands, but also the resonant plasmons’ frequencies, above and below the plasma frequency. We show that, besides the strong influence of the incidence angle and the characteristic low transmission of a single conductor slab for frequencies ω below the plasma frequency ω p , the coherent coupling of the bulk plasmon modes and the interface surface plasmon polaritons lead to oscillating transmission coefficients and, depending on the parity of the number of unit cells n of the superlattice, the transmission coefficient vanishes or amplifies as the conductor width increases. Similarly, the well-established transmission coefficient of a single left-handed slab, which exhibits optical antimatter effects, becomes highly resonant with superluminal effects in superlattices. We determine the space-time evolution of a wave packet through the λ / 4 photonic superlattice whose bandwidth becomes negligible, and the transmission coefficient becomes a sequence of isolated and equidistant peaks with negative phase times. We show that the space-time evolution of a Gaussian wave packet, with the centroid at any of these peaks, agrees with the theoretical predictions, and no violation of the causality principle occurs.
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Geyer, Christoph, Andreas Müller, and Barbara Wehle. "Measurements of thermal Transmittance of an External massive timber wall in-situ and in the Laboratory." E3S Web of Conferences 172 (2020): 14009. http://dx.doi.org/10.1051/e3sconf/202017214009.

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Анотація:
The thermal transmittance of an exterior massive timber wall was measured in situ in Appenzell, Switzerland according to the standard ISO 9869-1. The measurements were performed with two different measurement sets in parallel. The measurements started in February and stopped at end of April. The measuring data were analyzed using mean values of the thermal transmittance coefficient and of the thermal resistance following the procedure of ISO 9869-1. In order to clarify if the in-situ measurement results show significant deviations from the measurement results of the thermal transmittance obtained in the laboratory, the thermal transmittance of the identical wall construction was measured in the laboratory of Bern University of Applied Sciences in Biel according to the standard EN ISO 8990 for steady state boundary conditions in a guarded and calibrated hot box. The test results will be presented and the measurement setup will be described. The calculation value of the thermal transmittance coefficient of the massive timber wall according to EN ISO 6946 is U = 0.53 W/(m2K). The test results of the thermal transmittance coefficient, U-value of the wall, measured in the hot box, agreed well within a confidence level of 95 % with the calculated value. The in-situ measurement results of the thermal transmittance coefficient of the two measurement sets differ significantly in the order of 8 % referred to the calculated U-value of the wall as the basic amount. Furthermore, both in situ test results of the U-value of the wall show significant deviations from the calculated U-value up to 27 %.
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8

Burger, T., J. Kuhn, R. Caps, and J. Fricke. "Quantitative Determination of the Scattering and Absorption Coefficients from Diffuse Reflectance and Transmittance Measurements: Application to Pharmaceutical Powders." Applied Spectroscopy 51, no. 3 (March 1997): 309–17. http://dx.doi.org/10.1366/0003702971940404.

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Анотація:
A measurement and data evaluation technique for the separate determination of the scattering and absorption properties of loose pharmaceutical powders is described. The equation of radiative transfer for diffuse reflectance and transmittance is analytically solved by using a three-flux approximation. Combined transmittance and reflectance measurements then allow one to derive both the scattering and the absorption coefficients. The scattering and absorption coefficients provide more information about particle size, degree of agglomeration, and chemical composition of the samples in comparison to the usual determination of only the ratio of the coefficients from diffuse reflectance measurements on optically thick samples. Furthermore, the theory of diffuse reflectance of optically thick samples according to Kubelka and Munk is compared to the three-flux approximation. The influence of the particle size on the scattering and absorption coefficient is investigated, and it is shown that the assumption of a wavelength-independent scattering coefficient, though often made in reflectance spectroscopy, is not generally valid.
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9

Journal, Baghdad Science. "Effects of Non-Thermal Argon Plasma Produced at Atmospheric Pressure on the Optical Properties of CdO Thin Films." Baghdad Science Journal 15, no. 2 (June 4, 2018): 221–26. http://dx.doi.org/10.21123/bsj.15.2.221-226.

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In this paper the effect of nonthermal atmospheric argon plasma on the optical properties of the cadmium oxide CdO thin films prepared by chemical spray pyrolysis was studied. The prepared films were exposed to different time intervals (0, 5, 10, 15, 20) min. For every sample, the transmittance, Absorbance, absorption coefficient, energy gap, extinction coefficient and dielectric constant were studied. It is found that the transmittance and the energy gap increased with exposure time, and absorption. Absorption coefficient, extinction coefficient, dielectric constant decreased with time of exposure to the argon plasma
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10

Abass, Khalid Haneen. "Spray Pyrolysis Deposition and Effect of Annealing Temperature on Optical Properties of Cu:NiO Film." International Letters of Chemistry, Physics and Astronomy 47 (February 2015): 178–84. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.47.178.

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Анотація:
Spray pyrolysis method that used to prepare Cu:NiO thin films onto glass substrate with various annealing temperature. Spectral transmittance of prepared thin films determined by UV-Visible spectrophotometer in the range of (380-900) nm. The transmittance decreased with increasing annealing temperature. While the absorption coefficient and extinction coefficient increased with increasing annealing temperature. Energy gap decreased from 2.9 eV before annealing to 2.78 eV after 500 °C annealing temperature.
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Більше джерел

Дисертації з теми "Coefficient of transmittance"

1

Доброжан, Олександр Анатолійович, Александр Анатольевич Доброжан, Oleksandr Anatoliyovych Dobrozhan, Таїсія Олександрівна Бересток, Таисия Александровна Бересток, Taisiia Oleksandrivna Berestok, Денис Ігорович Курбатов, et al. "Optical Losses of Thin Solar Cells on the Basis of n-ZnS / p-CdTe and n-CdS / p-CdTe Heterojunctions." Thesis, Sumy State University Publishing, 2013. http://essuir.sumdu.edu.ua/handle/123456789/33898.

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Анотація:
The optical reflection and absorption losses in the accessory layers of solar cells based on n-ZnS / p- CdTe and n-CdS / p-CdTe heterojunctions are defined in this work. Aluminum doped zinc oxide is used as the front conductive layer material. It is shown that the replacement of traditional window material (CdS) for a wide-one (ZnS) leads to an increase in accessory solar cells layers transmittance. When the thickness of the window layers is 50 nm, the transmittance using ZnS windows with the wavelength of 380-500 nm is higher in 7-40 % than the corresponding value for CdS. At 300 nm for the same spectral field the difference increases to 8-89 %. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33898
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2

Dobrozhan, O. A., T. O. Berestok, D. I. Kurbatov, A. S. Opanasyuk, N. M. Opanasyuk, and V. F. Nefedchenko. "Optical Losses of Thin Solar Cells on the Basis of n-ZnS / p-CdTe and n-CdS / p-CdTe Heterojunctions." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35590.

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Анотація:
The optical reflection and absorption losses in the accessory layers of solar cells based on n-ZnS / p- CdTe and n-CdS / p-CdTe heterojunctions are defined in this work. Aluminum doped zinc oxide is used as the front conductive layer material. It is shown that the replacement of traditional window material (CdS) for a wide-one (ZnS) leads to an increase in accessory solar cells layers transmittance. When the thickness of the window layers is 50 nm, the transmittance using ZnS windows with the wavelength of 380-500 nm is higher in 7-40 % than the corresponding value for CdS. At 300 nm for the same spectral field the difference increases to 8-89 %. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35590
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3

Лозінський, Владислав Валентинович. "Моделювання звукопровідної системи середнього вуха людини в Comsol". Master's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/33851.

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Анотація:
Дослідження слухових властивостей слухової системи людини є актуальною проблемою сьогодення, адже здоровий слух це запорука нормального життя. Серед об’єктивних методів, таких як імпендасометрія, дослідження проводять з застосуванням пневмосистеми, що робить неможливим проведення процедури для немовлят. Саме тому запропоновано дослідження на основі ехо-спектрометру, який є вдосконаленим об’єктивного методу без використання пневмосистеми та з простою процедурою вимірювань і обробки для розширення вікової групи та покращенням точності результатів. При наявності великого спектру можливостей для діагностики слуху, майже нічого не відомо про акустичні характеристики звукопровідної системи людини, вже десятки років вчені займаються вивченням середнього вуха. Також широке застосування набуло використання протезів для реконструкції вуха при пошкодженнях його органів слуху. Проте сказати наскільки ці методи ефективні важко. Тому ця робота присвячена моделюванню звукопровідної системи, замінника, порівнянням цих моделей та оцінці ефективності запропонованого методу діагностики слуху. Основною задачею є отримання коефіцієнту проходження, який дасть змогу відповісти на питання як саме себе поводить звукопровідна система та наскільки протези є ефективними для реконструкції слуху.
The study of the auditory properties of the human auditory system is an urgent problem today, because healthy hearing is the key to a normal life. Among the objective methods, such as impedancemetry, research is performed using a pneumatic system, which makes it impossible to perform the procedure for infants. That is why the study is based on an echo spectrometer, which is an improved objective method without the use of a pneumatic system and with a simple measurement and processing procedure to expand the age group and improve the accuracy of the results. With a wide range of opportunities for the diagnosis of hearing, almost nothing is known about the acoustic characteristics of the human sound system, for decades, scientists have been studying the middle ear. The use of prostheses for the reconstruction of the ear in case of damage to its hearing organs has also become widely used. However, it is difficult to say how effective these methods are. Therefore, this work is devoted to modeling the sound conduction system, substitute, comparing these models and evaluating the effectiveness of the proposed method of hearing diagnosis. The main task is to obtain the transmittance, which will answer the question of how the sound system behaves and how effective prostheses are for the reconstruction of hearing.
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4

Tůmová, Eliška. "Tvorba mikroklimatu průmyslové haly s vysokými nároky na jeho rovnoměrnost." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227487.

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This diploma thesis deals with the optimization of microclimate of an industrial building. There is required constant temperature with minimal fluctuations during manufacturing process in the building. Due to insufficient cooling power of air-conditioning system was objective to design a solution that ensures stability of internal temperature during production especially in summer and simultaneously should be the solution economically acceptable. Simulation shows original state defined problems. Some new or unusual materials for solar shading are reviewed in the thesis by the experimental measurements and by the comparative method. To each material is assigned shading coefficient according to Czech standards, thereby is achieved universality for calculations of heat gains resulting from solar radiation. By one part of the experiments and their evaluation is determined thickness of the standard single glass glazing. It is also determined proportional transmittance of solar radiation for certain multiwall polycarbonates, which are currently used as fillers of industrial skylights and production hall‘s window openings. From experiments resulting design is subjected to the simulation. Comparison of temperatures is shown for the time before the installation of designed solar shading and after the installation of the solar shading.
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5

Hejný, Lukáš. "Tepelně technické vlastnosti rámu okenní výplně a připojovací spáry." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-234552.

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Анотація:
This thesis deals with the solution problem of fitting a window in the wall, especially for passive houses. It provides options to optimize the window connection joints, improve the thermal transmittance of the window frame, thereby reducing the total heat loss through the window. In the first part of the thesis is a research literature on the windows and heat technical and physical mechanisms. Are described equations and physical processes taking place in the windows and related building structures. This section describes the basic points in history, technical description of windows, etc. and present ways of assembly Installation the window and the influence of the thermal properties of the heat loss. The next part deals with the description of the work and the results obtained in the course of doctoral study. Describes the main objectives of the dissertation thesis, calculations and simulations of temperature fields and the results of the calculated values. Furthermore are described and analyzed measurement data and compared with the calculated values. At the end dissertation thesis are given opportunities to improve the current solution regarding the heat transfer coefficient of the frame, the optimal way of installation fillers windows in the perimeter wall and improve the thermal properties of the connecting joint.
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6

Svoboda, Lukáš. "Studie snížení energetické náročnosti bytového domu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226693.

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Анотація:
The goal of the thesis is firstly to get all the information about the initial state of solved block of flats, which is located on the street Merhautova 76/954 in Brno – Černá pole, in terms of constructions, energy consumption and initial state of heating system. In the second part of the thesis, where are discussed the possibilities of reduction of energy consumption, variant drafts of reduction of energy consumption and their financial costs and the choice of optimal variant. Third part deals with assement of solved block of flats in terms of sustainable built environment by using tool to rate buildings in terms of sustainable built environment - SBToolCZ, evaluation of possibility to use renewables. In the end are written summaries and recommendations.
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7

Abreu, Luís Cláudio da Costa. "Impacto dos parâmetros do isolamento nas pontes térmicas lineares em regime sazonal e dinâmico." Master's thesis, 2021. http://hdl.handle.net/10316/96176.

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Анотація:
Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia
A necessidade de melhorar o desempenho energético dos edifícios e de reduzir a emissão de gases com efeito de estufa impõe que se utilizem isolamentos térmicos com caraterísticas e espessuras adequadas. Atualmente existem inúmeros materiais que atuam como isolantes e a sua eficiência depende da sua posição na solução construtiva e dos parâmetros associados, nomeadamente a sua espessura e condutibilidade térmica. O estudo da eficácia do isolamento é fundamental para garantir conforto habitacional e níveis adequados de desempenho energético.No contexto desta dissertação é estudado o impacto que vários parâmetros têm nas perdas de calor das pontes térmicas lineares. Além do impacto dos materiais construtivos, foi visto em detalhe a influência da espessura e condutibilidade térmica dos isolamentos térmicos. Como as exigências regulamentares obrigam à aplicação de grandes espessuras, será dado particular atenção a este aspeto. Também a posição do isolamento será alvo de análise. Este trabalho propõe equações expeditas para determinar o coeficiente de perda linear de um conjunto de soluções construtivas.Numa segunda fase do trabalho é investigado o efeito das pontes térmicas lineares na modelação dinâmica do desempenho energético de edifícios residenciais. Para esse efeito é analisada uma fração multifamiliar utilizando o EnergyPlus. São avaliadas cinco situações de isolamento e condutibilidade térmica e comparados os resultados para dois regimes, sazonal e dinâmico. Para se compreender a importância das pontes térmicas lineares, são comparadas as perdas de calor pelas paredes com as perdas pelas pontes térmicas lineares.
In order to improve the energy performance of buildings and reduce greenhouse gas emissions, it is necessary to use thermal insulation with suitable characteristics and thicknesses. Currently there are numerous materials that act as insulators and their efficiency depends on their position in the construction solution and the associated parameters, particularly their thickness and thermal conductivity. The study of the effectiveness of insulation is essential to ensure residential comfort and adequate levels of energy performance.In this paper we study the impact that different parameters have on the heat loss of linear thermal bridges. In addition to the impact of construction materials, the influence of thickness and thermal conductivity of thermal insulations was examined in detail. As the regulation demands the application of large thicknesses, the position of the insulation will also be analysed. This work proposes expedite equations to determine the linear loss coefficient of a set of building solutions.In a second stage, the effect of linear thermal bridges in the dynamic modelling of the energy performance of residential buildings is investigated. For this purpose, a multifamily unit is analysed using EnergyPlus. Five situations of insulation and thermal conductivity are evaluated, and the results are compared for two regimes, seasonal and dynamic. To understand the importance of linear thermal bridges, the heat losses through the walls are compared with the losses through linear thermal bridges.
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8

黃泰碩. "An inverse radiation analysis for estimation of color matching coefficients from reflectance and transmittance measured by spectrometer." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33031346358140083286.

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Книги з теми "Coefficient of transmittance"

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Atomic oxygen texturing of polymers and carbons. [Washington, DC: National Aeronautics and Space Administration, 1997.

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Частини книг з теми "Coefficient of transmittance"

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Brunel, P., L. Lavanant, and G. Rochard. "Transmittance Coefficient Generation for Fast Radiative Transfer Models: Application to New Satellite Sounding Systems." In High Spectral Resolution Infrared Remote Sensing for Earth’s Weather and Climate Studies, 431–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84599-4_29.

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Thomas, Michael E. "Experimental Techniques." In Optical Propagation in Linear Media. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195091618.003.0010.

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This chapter presents basic experimental techniques and various apparatus for measuring the complex index of refraction and related quantities. Generally, measurements of transmittance, reflectance, and emittance are made using spectrometers or lasers. Other important techniques, which measure directly the real refractive index, n, the absorption coefficient, βabs , and the scattering coefficient, βsca, such as interferometry, ellipsometers, calorimetry, and scatterometers, are also introduced. Ultimately, experimental procedures must be taught in the laboratory. Thus, devoting only one chapter to experimental technique and five to theory is not indicative of the importance of this fundamental topic. By discussing the measurement of basic optical parameters, it is intended that the concepts developed in the first five chapters will be reinforced. All of the theoretical models developed in the previous chapters contain measurable parameters. Basic theory often helps guide the design of a good experiment. Once data is available, it can be used to check the assumptions of the theory. This interplay between experiment and theory is an essential part of definitive work. The chapter has two main parts; the first covers measurements of the real and imaginary parts of the complex index of refraction and the second covers measurements of scattering. As established in Chapter 2, the characterization of bulk absorption mechanisms on optical propagation is accomplished by the complex index of refraction. Considerable effort was expended in Chapters 3, 4, and 5 to obtain models of the complex index. Thus, at this point, we wish to find ways to experimentally measure the complex index of refraction for various media. The broad-band spectral response of a medium is commonly measured by a spectrometer. There are two main types of spectrometers, dispersive and interferometric. Generally, spectrometers make broad-band transmission, emission, and reflection measurements, and therefore indirectly measure, n̄. Interferometric measurements, are the exception. Lasers, which feature narrow-band, high-intensity, highly directional light are often used to complement and calibrate broad-band spectrometer measurements. The highest accuracy measurements of the absorption coefficient are obtainable by laser techniques, which can directly measure the components of the complex index.
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Тези доповідей конференцій з теми "Coefficient of transmittance"

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Wang, Jiaqi, Jeffery C. C. Lo, S. W. Ricky Lee, Feng Yun, and Mian Tao. "Modeling and Parametric Study of Light Scattering, Absorption and Emission of Phosphor in a White Light-Emitting Diode." In ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems collocated with the ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ipack2015-48664.

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In this study, we proposed and demonstrated an effective approach to model and predict spectral power distribution (SPD) for a phosphor-converted light emitting diode (pc-LED). For emission and excitation, broadband diffuse transmittances of 1 mm YAG:Ce phosphor plates with different concentrations were measured by a spectrophotometer. For emission, it was found that transmittance for all wavelengths was almost identical. This result indicates that emission spectrum prediction could be simplified by simulating the radiant power of the peak wavelength only. At the peak wavelength (560 nm), our simulation results, in which optical constants were calculated by the Lorenz-Mie theory, agreed well with our measurements. For excitation, a novel transmittance measurement setup based on an LED goniophotometer was proposed to obtain the absorption coefficient. By adjusting the optical parameter in our ray-tracing model to fit measured transmittances, accurate absorption coefficients were determined. Based on our calculation and measured optical parameters, we simulated the radiant power of the blue light and yellow light of commercial white LED packages. By expanding the total blue and yellow power into linear combinations of wavelengths in both regions, we successfully predicted the SPD of our LED package. Our predicted SPD has good agreement with the measured results.
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Qiu, G., and S. B. Riffat. "Theoretical Investigation of Solar Transmittance of Transparent Honeycombs." In ASME 2003 International Solar Energy Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/isec2003-44004.

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Transparent honeycombs are a type of transparent insulation material (TIM) offering significant benefits in terms of solar energy engineering and energy saving in buildings. Two of the most important characteristics of transparent honeycombs are their solar transmittance for solar radiation and heat loss coefficient for long wave thermal radiation. This paper presents a calculating model for solar transmittance for ideal transparent honeycombs and real transparent honeycombs. Theoretical calculations are compared to measured transmittance of square-celled polycarbonate honeycomb panels with a high degree of correlation. The solar transmittance of real transparent honeycombs is found to be strongly dependent on honeycomb cell hydraulic diameter and specular transmissivity of the honeycomb wall for a solar beam incident at angle φ.
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Larruquert, Juan I., Mónica Fernández-Perea, José A. Aznárez, José A. Méndez, Luca Poletto, Denis Garoli, A. Marco Malvezzi, Angelo Giglia, and Stefano Nannarone. "Determination of the transmittance and extinction coefficient of Yb films in the 23-1700 eV range." In SPIE Optics + Photonics, edited by Ali M. Khounsary and Christian Morawe. SPIE, 2006. http://dx.doi.org/10.1117/12.680930.

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Yang, Gang, and Changying Zhao. "Experimental Study of Wide-Range Spectral Radiation Properties of Air Plasma Sprayed Thermal Barrier Coatings." In ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/mnhmt2013-22041.

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In this paper the radiative properties of air plasma sprayed (APS) thermal barrier coatings are investigated by measuring the spectral diffuse reflectance and transmittance of samples with various thickness and porosities in a broad spectral band ranging from 0.25 to 15μm. The spectral absorption and scattering coefficients are obtained by a four flux model based on the experimental data. The results show that the porous zirconia ceramics exhibits high scattering coefficient (> 15000 m−1) and low absorption coefficient (< 500 m−1) in the spectral range from 0.5 to 6μm, and the corresponding spectral scattering albedo reaches up to 0.99. In addition, this study also found that the spectral scattering coefficient increases with increasing porosity, while the spectral absorption coefficient is not quite sensitive to the change of porosity. This result confirms the fact that scattering is mainly caused by the refractive index mismatch between bulk YSZ and internal void. Spectral scattering coefficient heavily depends on the microstructures of coatings, i.e., pore size, porosity and pore distribution, and this will in turn considerably affect the thermal radiation heat transfer inside the coating.
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Fernández-Perea, Mónica, José A. Aznárez, Juan I. Larruquert, José A. Méndez, Luca Poletto, Denis Garoli, A. Marco Malvezzi, Angelo Giglia, and Stefano Nannarone. "Transmittance and extinction coefficient of Ce films measured in situ in the extreme ultraviolet and soft x-rays." In SPIE Optics + Photonics, edited by Ali M. Khounsary and Christian Morawe. SPIE, 2006. http://dx.doi.org/10.1117/12.684339.

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Sicard, Michael, Francesc Rocadenbosch, Adolfo Comeron та Miguel Angel Lopez. "Iterative method for the retrieval of the aerosol backscatter coefficient and the Ångstrom exponent from bi-wavelength lidar data in low-transmittance atmospheres". У Remote Sensing, редактори Adolfo Comeron, Michel R. Carleer, Richard H. Picard та Nicolaos I. Sifakis. SPIE, 2004. http://dx.doi.org/10.1117/12.565621.

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Tian, Weixue, Wei Huang, and Wilson K. S. Chiu. "Hemispherical Emittance of a Semitransparent Fiber Coated With a Submicron Absorbing Film." In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72519.

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This study presents a model to predict the directional and hemispherical emittance of a fiber coated with up to 2 μm film. The fiber is composed of semitransparent media with a small extinction coefficient. Transmittance and reflectance of the thin film is calculated based on the flat thin film assumption, because the thickness of the film is much less than the fiber radius, and the curvature can be neglected. Predicted emittance from wave optics is compared to geometric optics for modeling radiative transfer in thin film. Steep changes in emittance are predicted by wave optics for films that are nanometers thick. This effect was not observed from geometric optics analysis. Effects of film and fiber substrate optical properties are also studied.
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Omarov, Rashit, Murat Kunelbayev, Omar Dauren, Tanirnazar Sultangaziyev, and Asan Baibolov. "SIMULATION METHODOLOGY FOR PILOT MODEL OF SOLAR WATER HEATING UNIT." In GEOLINKS Conference Proceedings. Saima Consult Ltd, 2021. http://dx.doi.org/10.32008/geolinks2021/b2/v3/39.

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In the given work there is shown the methodology of simulating the experimental model of solar water heating unit. Using theoretical and experimental outcomes, also, obtained rated values of transmittance medium in solar collector, there has been carried out predictive analysis of solar irradiation flow density, ambient temperature and temperature in the accumulator tank. Estimated and experimental daily characteristics of both systems have efficient accuracy of 7%, which proves reliability of constructive formulae and engineering model. As well, there has been computed the unit capacity factor, plants’ production growth constitutes from 0.5 to 0.85%. Computed the coefficient, which depends on heat flow and solar collector’s surface, as well on convective heat exchange between solar irradiation and solar collector’s surface. Experimentally executed computation of solar water heating unit’s performance, which is fulfilled in compliance with hourly sums of direct and scattered irradiation and ambient temperature
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Ganesan, Krithiga, Jaona Randrianalisoa, and Wojciech Lipiński. "Effect of Morphology on Spectral Radiative Properties of Three-Dimensionally Ordered Macroporous Ceria Packed Bed." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17382.

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In this paper, radiative characterization of a packed bed of novel three-dimensionally ordered macroporous (3DOM) ceria particles is performed in the spectral range relevant to solar thermochemical processes, 0.35–2.2μm. Normal–hemispherical transmittance and reflectance of three samples of various thicknesses are measured. Monte Carlo ray-tracing and discrete ordinate methods are employed to identify transport scattering albedo and transport extinction coefficient in the spectral range corresponding to weak absorption in the semi-transparency band of ceria. 3DOM ceria particles are characterized by weaker scattering in comparison to sintered ceria ceramics, and increased transparency in the near-infrared spectral range 0.7–2 μm. The ordered pore-morphology of the 3DOM ceria after thermochemical redox cycling between temperatures 1373 K and 1073 K is altered due to sintering of walls of the 3DOM structure. The absorption coefficient of the packed bed is found to be practically independent of morphology. Radiative characterization of 3DOM ceria ceramics before and after thermochemical cycling suggests that preserving the 3DOM structure can lead to scattering characteristics that permit longer attenuation path lengths of incident concentrated solar radiation in the material, as well as be favorable for confinement of the near-infrared radiation during thermochemical cycling leading to favorable thermochemical conditions for fuel production.
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Wang, Yao, Pei-feng Hsu, and Yingsang Wu. "Near Infrared Radiative Properties of Thermal Barrier Coatings." In ASME 2021 Heat Transfer Summer Conference collocated with the ASME 2021 15th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/ht2021-61258.

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Abstract Thermal barrier coatings are widely used in gas turbines to protect the gas turbine metal components against very high combustion product temperature. To improve energy efficiency, higher combustion temperatures are needed. A limiting factor at present is the stability under extreme and prolonged heating of thermal barrier coatings. The coatings are typically made by the air plasma sprayed process in which fine particles of yttria-stabilized zirconia (YSZ) are melted or partially melted and ejected from plasma jet at high speed onto the bond coated substrate metal. With increasing combustion temperature and pressure in the modern gas turbine engines radiative heat transfer is becoming an important portion of the overall heat transfer in the thermal barrier coating. This study has demonstrated that the commonly used Kubelka-Munk method in the radiative property reduction from the measured transmittance and reflectance spectra of YSZ coatings will incur inaccurate result when the coating optical thickness is not sufficiently large. An alternative method — the discrete ordinates method with the asymmetric spherical ring angular quadrature — is used instead. The absorption and scattering coefficients of air plasma sprayed YSZ films are determined over the wavelength range from 1 to 2.6 μm at room temperature. Over this near infrared wavelength range, the scattering coefficient decreases with the increasing wavelength and the absorption coefficient is very small overall. The pore size distributions before and after the 50-hr temperature gradient, thermal cycling are compared. The sintering effect as well as the crack growth will impact the coating radiative properties. These results point to a clear need for better understanding of the radiative heat transfer process, which includes the microstructure-property relationship, progressive changes of the radiative properties with the operation condition and time.
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Звіти організацій з теми "Coefficient of transmittance"

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Kantrowitz, Frank T., William M. Gutman, and Troy D. Gammill. Determination of Spectrally Resolved Transmittance and Extinction Coefficients for Obscurants at Smoke Week XIV. Fort Belvoir, VA: Defense Technical Information Center, September 1994. http://dx.doi.org/10.21236/ada286473.

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