Cottrell s longtime interest in nitrogen fixation prompted a collaboration with Farrington Daniels of the University of Wisconsin, beginning in 1939 . Daniels and associates were trying to develop a thermal process for nitrogen fixation using a regenerative pebble-bed furnace, which they hoped would be an inexpensive alternative to the Haber ammonia synthesis.
32.
D2T2 is a three colour ( Yellow, Cyan & Magenta ) thermal process whereby the colour dyes are transferred from an ink ribbon onto, or rather into, the surface of a special paper substrate . " Dry labs " are becoming increasingly popular with users as they are cheaper and easier to maintain than wet labs.
33.
The high temperatures require energy to be carried from the solar interior to the corona by non-thermal processes, because the second law of thermodynamics prevents heat from flowing directly from the solar photosphere ( surface ), which is at about 5800 K, to the much hotter corona at about 1 to 3 MK ( parts of the corona can even reach 10 MK ).
34.
Hypotheses of origin generally fall into two categories : one, the dichotomy was produced by a mega-impact event or several large impacts early in the planet s history ( exogenic theories ) or two, the dichotomy was produced by crustal thinning in the northern hemisphere by mantle convection, overturning, or other chemical and thermal processes in the planet s interior ( endogenic theories ).
