Identification method for infrared absorption spectra of semitransparent media by their emission data Application to lime-aluminosilicate glasses at high temperatures

The infrared absorption spectra of four Ume-aluminosihcate glasses have been studied at high temperatures in the spectral range 1 to 5 µm. The glass composition varies essentially by the FeO content. The effect of temperature is pointed out up to 1450 °C. The emission spectrometry technique used is appHed to thin slabs of semitransparent materials heated in plane-parallel platinum crucibles exposed to strong temperature gradients. The absorption coefficient is identified, for each wavelength, by a non-linear constraint optimization technique. As an illustration of the major influence of the spectrum on the heat exchanges in semitransparent devices, a modeling of the combined conductive/radiative heat transfer is performed in a glass wall

Polarized Light-Pulse Transport Through Scattering Media

The propagation of a polarized pulse in random media is investigated using the discrete-ordinates method to solve the transient vector radiative transfer. The angular analysis of the transient polarized features of scattering fluxes makes it possible to investigate subtle details of the polarization flip encountered for circularly polarized waves. We found that, depending on the geometry, the state of polarization, and the angle of detection, the degree of polarization decays at either a slower or faster rate when the beam is impinging at an angle far from the normal incidence. At normal incidence, our results confirm that, for large particles, the circular polarization maintains a greater degree of polarization. © 2006 Optical Society of America

Mechanical and Thermal Behavior of Compressed Earth Bricks Reinforced with Lime and Coal Aggregates

The present study aims to investigate the effect of coal aggregates (CA) in the compressed earth bricks (CEBs) in order to reduce the footprint of the coal industry. For this purpose, three soils of the Marrakesh region were studied in terms of their chemical composition, and their thermal and mechanical behavior. Then, the selected soil was mixed with different amounts of CA (10%, 15%, and 20% by weight) and compressed in a Brava machine to produce (CEBs). A significant drop in the specific weight of our CEBs was registered with the increase of CA percentage. Besides, the compressive strength showed a linear drop with the increase of (CA) percentages. In fact, for bricks with 20% of CA, the decrease in compressive strength reaches 32.95% in respect to the reference bricks. Moreover, CA showed interesting gain in thermal conductivity reaching 60% while the diminution in compressive strength was still acceptable according to norms in the state of the art. Thereby, we can say that using CA in earth bricks can, with the suitable architecture, contribute not only to reduce the building charges, but also to provide a good thermal comfort without increasing the thickness of the walls