scholarly journals Spectroscopy in heterogenous media and applications for bioprocess and environmental monitoring

2002 ◽  
Vol 4 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Frank Schael ◽  
Oliver Reich ◽  
Sonja Engelhard
Keyword(s):  
Diffuse Reflectance ◽  
Near Infrared ◽  
Transport Theory ◽  
Radiation Transport ◽  
Diffusion Theory ◽  
Nile Blue ◽  
Milk Powder ◽  
Photon Migration ◽  
Heterogenous Media ◽  
Reflectance Measurements

Diffuse reflectance measurements and photon migration studies with near infrared (NIR) diode lasers were employed to elucidate experimental methods for determining absorption and scattering coefficients and species concentrations in heterogenous media. Measurements were performed at a number of wavelengths utilizing several laser sources some of which were widely tunable. In order to establish the applicability of simple photon migration models derived from radiation transport theory and to check the experimental boundary conditions of our measurements, simple light scattering solutions (such as suspensions of titanium dioxide, latex particles, and solutions of milk powder) containing dyes (such as nile blue, isosulfan blue) were investigated. The results obtained from diffuse-reflectance studies at different sourcedetector distances were in accordance with predictions from simple photon diffusion theory. Applications of reflectance measurements for monitoring of cell growth during fermentation processes and forin-situinvestigations of soils are presented.

scholarly journals Retrieval of Dust Properties From Spectral Snow Reflectance Measurements

2021 ◽  
Vol 9 ◽  
Author(s):  
Alexander Kokhanovsky ◽  
Biagio Di Mauro ◽  
Roberto Garzonio ◽  
Roberto Colombo
Keyword(s):  
Grain Size ◽  
Mass Concentration ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Spectroscopy Data ◽  
Field Spectroscopy ◽  
Dust Mass ◽  
The Alps ◽  
Simplified Algorithm ◽  
Reflectance Measurements

In this paper, we present a simplified algorithm to retrieve snow grain size, dust mass absorption coefficient and dust mass concentration from spectral diffuse reflectance measurements at three wavelengths located in the visible and near infrared. The theoretical model is then compared with field spectroscopy data collected in different days from an automated spectrometer in the Alps.

A Method to Obtain Diffuse Reflectance Measurements from 1.0 to 3.0 µm Using a Cary 17I Spectrophotometer

1977 ◽  
Vol 31 (5) ◽  
pp. 463-465
Author(s):  
James B. Gillespie ◽  
James D. Lindberg
Keyword(s):  
Spectral Region ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Accessory Cell ◽  
Spectral Interval ◽  
Gypsum Crystal ◽  
Pure Grade ◽  
A Minor ◽  
Reflectance Measurements ◽  
Electronic Amplifier

This paper describes a way to perform diffuse reflectance measurements over the 1.0 to 3.0 µm spectral interval by using a Cary 171 spectrophotometer equipped with inexpensive standard accessory cell-space integrating spheres. The method involves coating the cell-space spheres with a powder of pure grade quenched sulfur and making a minor alteration in an electronic amplifier. A spectrum of ground gypsum crystal in the 2.6 to 3.0 µm spectral region and a spectrum of a layer of hectorite clay in the 1.0 to 3.0 µm spectral region are presented to illustrate the applicability of the above technique for making diffuse reflectance measurements in the near infrared.

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