scholarly journals Unique Determination of Absorption Coefficients in a Semilinear Transport Equation

2021 ◽  
Vol 53 (5) ◽  
pp. 5158-5184
Author(s):  
Kui Ren ◽  
Yimin Zhong
Keyword(s):  
Transport Equation ◽  
Unique Determination ◽  
Absorption Coefficients

The Calculation of Turbulent Diffusion Coefficients in Aquatic Ecosystems

2019 ◽  
Vol 70 (11) ◽  
pp. 3903-3907
Author(s):  
Galina Marusic ◽  
Valeriu Panaitescu
Keyword(s):  
Transport Equation ◽  
Turbulent Diffusion ◽  
Diffusion Coefficients ◽  
Aquatic Ecosystems ◽  
Specific Area ◽  
Left Bank ◽  
The Right ◽  
Prut River

The paper deals with the issues related to the pollution of aquatic ecosystems. The influence of turbulence on the transport and dispersion of pollutants in the mentioned systems, as well as the calculation of the turbulent diffusion coefficients are studied. A case study on the determination of turbulent diffusion coefficients for some sectors of the Prut River is presented. A new method is proposed for the determination of the turbulent diffusion coefficients in the pollutant transport equation for specific sectors of a river, according to the associated number of P�clet, calculated for each specific area: the left bank, the right bank and the middle of the river.

The Use of Reverse Mirage Spectroscopy to Determine the Absorption Coefficient of Liquid Methanol at CO2 Laser Wavelengths

1989 ◽  
Vol 43 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Dane Bićanić ◽  
Siegfried Krüger ◽  
Paul Torfs ◽  
Bruno Bein ◽  
Frans Harren
Keyword(s):  
Absorption Coefficient ◽  
Co2 Laser ◽  
Probe Beam ◽  
Laser Emission ◽  
Wavelength Region ◽  
Experimental Setup ◽  
Absorption Coefficients ◽  
Experimental Conditions ◽  
Liquid Samples

An experimental setup for performance of reverse mirage spectroscopy at CO2 laser wavelengths on liquid samples having high values of absorption coefficients is described. One and the same liquid is used as both the absorbing and deflecting medium. The Rosencwaig-Gersho theory has been applied, and the choice of experimental conditions that would enable determination of absorption coefficient β from the magnitude of photothermal signals measured at two different probe beam distances (probing locations) is discussed. The usefulness of this technique (essentially not inhibited by the requirements imposed on the sample's thickness) is tested on methanol having absorption coefficients β close to 300 cm−1 in the wavelength region covered by CO2 laser emission.

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