Total transmittance/absorption

A dimensionless quantity, symbolized by t or T, equal to the transmitted radiant power, Ptr, divided by the radiant power incident on the sample, Po thus, t = Ptr/ Pq. It is a measure of the ability of a body, solution, entity, eta, to transmit electromagnetic radiation. It is synonymous with transmission factor. See also Internal Transmittance Transmission Density Total Transmittance Beer-Lambert Law Absorption Spectroscopy... 

INTERNAL TRANSMITTANCE TRANSMISSION DENSITY TOTAL TRANSMITTANCE BEER-IAMBERT LAW ABSORPTION SPECTROSCOPY Transoid conformation,... 

Internal transmittance refers to energy loss by absorption, whereas the total transmittance is that due to absorption, reflection, scatter, etc. 

Note that even a small absorption of each reflecting surface results in a drastic reduction of the total transmittance. For A = 0.05, R = 0.9 T = 0.05 r /(l — RY = 0.25. This illustrates, that even for a small absorption of = 5 % the transmitted intensity drops to 25 % of the absorption-free transmittance,... 

The total transmittance of a multiple-stage filter is the product of the individual filter stage transmittances and has a sine function profile, shown in Fig. 8D. An LCTF based on the Lyot filter geometry having a maximum peak transmittance of 16%, a continuously tunable bandpass of 7.6 cm and a free spectral range of greater than 4600 cm" (500-650 nm) has been demonstrated [23]. However, a significant fraction of peak transmission loss in the Lyot LCTF is due to absorption by the polarizers and imperfect wave-plate action [24]. 

Total transmittance, diffuse reflectance and collimated transmittance are measured in the 200-2200 nm wavelength range using commercially available Varian Cary 5E, 500 or 2415 spectrophotometers with an internal integrating sphere [19, 21, 26, 75, 76]. To reconstract the absorption and reduced seattering coefficients of a tissue from such... 

Measurement over long view path (up to 100 km) with suitable illumination and target, contrast transmittance, total extinction, and chromaticity over sight path can be determined includes scattering and absorption from all sources can detect plume blight automated... 

ISO 1600 1990 Plastics - Cellulose acetate - Determination of light absorption on moulded specimens produced using different periods of heating ISO 13468-1 1996 Plastics - Determination of the total luminous transmittance of transparent materials - Part 1 Single-beam instrument ISO 13468-2 1999 Plastics - Determination of the total luminous transmittance of transparent materials - Part 2 Double-beam instrument ISO 14782 1999 Plastics - Determination of haze for transparent materials... 

LP-CVD ZnO Total and diffuse transmittance (TT and DT) for boron-doped LP-CVD ZnO films are shown in Fig. 6.17 as a function of the film thickness. TT remains superior to 85% in the spectral range [500-900 nm] for ZnO layers with d < 1.5 pm. Because 15% of the incident light is reflected due to the change of refractive index at the air/ZnO and glass/air interfaces, this means that, for d < 1.5 pm, the absorption of the LP-CVD ZnO B itself is too low to be measured by the spectrometer. TT is reduced by only about 5% for a thickness d = 3 pm. This means that 3 pm-thick ZnO films still have a high transparency, in spite of their relatively high thickness. For A > 900 nm,... 

LP-CVD ZnO Optical total and diffuse transmittance spectra (TT and DT spectra) of a temperature series of undoped LP-CVD ZnO films are shown in Fig. 6.25 TT does not vary strongly with substrate temperature. Indeed, as Fig. 6.25 is related to a series of undoped samples, the values of carrier density N are too low to produce an observable free carrier absorption effect... 

In photochemistry and photochemical technology, conditions with Aio 2 are usually designated as total absorbance, or in the past as total absorption (Braun et al., 1991) of UV/VIS radiation. Thus, for Aio 2 the transmittance T is less than 0.01. 

Aerosol particle optical thickness AOT, Dimensionless Tep = J Oep Total optical thickness (or commonly optical depth) T= — In r cos 0g, where T is transmittance of direct solar beam for solar zenith angle 0q optical thickness (or commonly optical depth) due to extinction by aerosol particles r p = t — Tg, where Tg is optical thickness arising from scattering and absorption by gases depends on wavelength... 

Of the various methods available for the determination of ozone in gaseous mixtures (4), the spectrophotometric methods, particularly the ultraviolet, appeared to be most suited for the purpose. These methods are all based on the strong absorption maximum for ozone in the ultraviolet at 254 mjm,. Thus, one can determine ozone concentration with a Beckman spectrophotometer by the usual procedure. Several other instruments (I, 3, 6) have been specifically designed to measure ozone concentrations by this photometric method. The meters constructed by the authors also operate on this principle. The total ozone stream, or an aliquot of known proportion, is passed through the meter and the per cent transmittance at 253.7 mju, is read from the dial. The ozone concentration at this temperature and pressure is then either determined from a calibration curve (Figure 1), constructed from titration data (the dial could bo calibrated directly in concentration units), or calculated (3) using Beer s law ... 

Spectroturbidimetry is simply measuring the loss of intensity of a light beam by absorption and scattering as it passes through a sample. In terms of transmittance T, the ratio of transmitted to incident intensity, and total absorbance A = -log10T,... 

Let us first estimate the transmittance of the atmosphere at the surface resulting from the absorption of solar radiation by 02. In (4.42), we need the total column abundance of 02 (molecules cm 2). From Chapter 1, estimation of the number concentration of air molecules at any altitude can be based on the scale height of the atmosphere... 

Up to this point we have assumed that only the aerosol in the atmosphere produces scattering and absorption. Actually the atmosphere itself, even if totally devoid of particles, does not completely transmit the incident solar beam. Let Ta denote the fractional transmittance of the atmosphere. It is useful to think of the atmosphere as overlaying the aerosol layer. Then, instead of Fo, the incident flux on the aerosol layer is TaF0. The total upward reflected flux, given by (24.4), is now corrected as follows ... 

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