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Materials for Optical Systems
Published in Anees Ahmad, Handbook of Optomechanical Engineering, 2017
Trent Newswander, Roger A. Paquin
Glasses are the most commonly used class of refracting material in optical systems. Glass is an amorphous material primarily composed of silica with additional materials added to alter the optical properties, chemical reactivity, and manufacturability. Boric oxide, alumina, alkaline earths, and alkali oxides are commonly added to produce high optical transparency and chemical resistance with the desired optical index and optical dispersion. Glass with a relatively low index and low dispersion are referred to as crown glass. Higher density material such as lead, zirconium, titanium, or other metal oxides are added to produce higher-index glass with higher dispersion, which is categorized as flint glass. Additionally, glass with longer infrared wavelength application is achieved by replacing the oxygen element with other elements of the chalcogenide group such as sulfur, selenium, or tellurium.37 For a more detailed discussion and explanation of the various terms used in describing the properties of optical glasses, see the study by Marker38 and the catalog Schott Optical Glass.39
Prisms and Refractive Optical Components
Published in Daniel Malacara-Hernández, Brian J. Thompson, Fundamentals and Basic Optical Instruments, 2017
Daniel Malacara-Hernández, Duncan T. Moore
Equilateral Prism. The simplest chromatic dispersing prism is the equilateral triangle prism illustrated in Figure 6.19. This prism is usually made with flint glass, because of its large refractive index variation with the wavelength of the light.
Land-use practices influence nutrient concentrations of southwestern Ontario streams
Published in Canadian Water Resources Journal / Revue canadienne des ressources hydriques, 2018
Kathryn E. Thomas, Renee Lazor, Patricia A. Chambers, Adam G. Yates
Water quality sampling was conducted approximately every 3 weeks from May to November 2012 for a total of 10 water samples per site. Grab water samples were collected in the thalweg at approximately 60% water depth and analyzed for major forms of P, namely total phosphorus (TP), total dissolved phosphorus (TDP), soluble reactive phosphorus (SRP), and N, namely dissolved Kjeldahl nitrogen (DKN), total nitrogen (TN), ammonia (NH3), and nitrate-nitrite (NO3 + NO2). One high-density polyethylene bottle (1 L) was filled and the water was field filtered (with 0.45-μm cellulose acetate filter paper) into sterile Flint glass bottles (125 mL) for analysis of NO3 + NO2, NH3, DKN, TDP and SRP. All samples were stored at approximately 4°C in a cooler and transported overnight to the National Laboratory for Environmental Testing (NLET) in Burlington, Ontario, for analysis following standard protocols (Environment Canada 1994). Concentrations of dissolved organic nitrogen (DON), dissolved inorganic nitrogen (DIN) and total dissolved nitrogen (TDN) were subsequently calculated from measured N forms. Calculated TDN values (DKN + [NO3 + NO2]) were sometimes slightly larger than measured TN due to the differing analytical methods used to measure the various N forms.
Prospects and physical limits of processes and technologies in glass melting
Published in Journal of Asian Ceramic Societies, 2019
In the heat balance (Figure 1; Equation (7)), the power Pht transferred from the combustion space to the melting space is a critical factor. Due to the large uncertainties at which wall losses, PwL, can be determined, Pht remains inaccessible by the heat balance. Therefore, an alternative approach is chosen. This rests on a simple (gray = wavelength-independent) radiation model. The features of this model are sketched in Figure 10. In general terms, the incident radiation (I) is transmitted (Tr), absorbed (Ab) or reflected (Rf): I = Tr + Ab + Rf. For heat radiation in a furnace, Tr is approximated as zero and the melt is treated as a surface radiator. This is a fair approximation for amber and Cr- green glass and still a useful one for flint glass. According to Kirchhoff’s law, the absorbed portion is equal to Em portion emitted as thermal radiation: I = Em + Rf. By Stefan-Boltzmann’s law, Em = ε·σ·T4, where 0 < ε < 1 is the emissivity of the radiating volume or surface and σ denotes the universal Stefan-Boltzmann constant σ = 56.7 · 10−12 kW/(m2·K4). A black body (ε = 1) at 1000 K thus emits 56.7 kW/m2. The balance of heat fluxes normalized to the exchange area, q = P/A in kW/m2, constitutes the following equation system:
TE Transmittance properties of one-dimensional symmetric quinary photonic crystals
Published in Journal of Modern Optics, 2021
Hassan S. Ashour, Mazen M. Abadla, Khedr M. Abohassan
Figure 8 shows the transmittance of the proposed structure when different materials of different refractive indices are used as central layers. The layer thickness is set to be 40 nm and the number of periods is 20. In this structure, the subsidiary layers are chosen as flint and dense flint glass. Figure 8 is split into two Figures (a) and (b) for the sake of clarity.