Techniques d’exploitation des mines de charbon

by Connaissance des Energies, 16 mars 2015

Les gisements sont des zones généralement profondes où l’on trouve de grandes quantités de charbon. Il faut forer des puits pour y accéder et extraire le minerai. Lorsque les réserves de charbon sont relativement proches de la surface de la terre, une exploitation à ciel ouvert peut être mise en place. Il existe également des gisements de charbon sous les océans, pour le moment inexploités.

Puerto Rico’s Hurricane History

by P.  Homewood, September 22, 2017 in NotaLotofPeopleKnowThat

As Hurricane Maria heads north as a Cat 3 storm, much is being made of the fact that it is the strongest hurricane to hit Puerto Rico since 1928. The implication is that Maria must have been exceptionally strong.

But the reality is that Puerto Rico is little more than a speck in the vastness of the Atlantic Ocean. The odds of the eye of a major hurricane, often just 10 or 20 miles wide, making a direct hit on Puerto Rico are probably hundreds to one, given that there are thousands of miles of ocean through which hurricanes can commonly travel.

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Study: plants are globally getting more efficient thanks to rising carbon dioxide

by University of California, September 12, 2017 in WUWT

A trend toward greater discrimination under higher CO2 levels is broadly consistent with tree ring studies over the past century, with field and chamber experiments, and with geological records of C3 plants at times of altered atmospheric CO2, but increasing discrimination has not previously been included in studies of long-term atmospheric 13C/12C measurements. We further show that the inferred discrimination increase of 0.014 ± 0.007‰ ppm−1 is largely explained by photorespiratory and mesophyll effects.