The Measurement of Solar Diameter and Limb Darkening Function with the Eclipse Observations

The Total Solar Irradiance varies over a solar cycle of 11 years and maybe over cycles with longer period. Is the solar diameter variable over time too? We introduce a new method to perform high resolution astrometry of the solar diameter from the ground, through the observations of eclipses by reconsidering the definition of the solar edge. A discussion of the solar diameter and its variations must be linked to the Limb Darkening Function (LDF) using the luminosity evolution of a Baily's Bead and the profile of the lunar limb available from satellite data. This approach unifies the definition of solar edge with LDF inflection point for eclipses and drift-scan or heliometric methods. The method proposed is applied for the videos of the eclipse in 15 January 2010 recorded in Uganda and in India. The result shows light at least 0.85 arcsec beyond the inflection point, and this suggests to reconsider the evaluations of the historical eclipses made with naked eye.Comment: 16 pages, 11 figures, accepted in Solar Physics. arXiv admin note: text overlap with arXiv:astro-ph/0601109 by other author

Transforming sludge into a recyclable and valuable carbon source by wet air oxidation

The wet air oxidation (WAO) process generates residual solids that can be landfilled without additional treatment. This practical advantage stems from the intrinsic leaching-resistant behaviour of the solids, which is linked to the treatment conditions in water at high temperature and to the composition of the solids. X-ray analysis confirmed that the fine powder (diameter 2-6 mu m) mainly comprises aluminium phosphates, kaolin, quartz, calcite and an amorphous fraction which immobilises heavy metals in the form of hydroxides, carbonates and insoluble phosphates. The residual solids contain a low amount of organic matter (1-2 wt.\% TOC, depending on the process parameters). They are easily settled and dewatered with dry solids (DS) content between 50 and 60\%. The re-use of WAO sludge supernatant as a carbon source in biological denitrification have been investigated. The initial results are deemed very satisfactory. The most significant results obtained during process development are reported in this paper