A process for the preparation of mononitroaromatics and dinitroaromatics, in which a hydrate melt of at least one metal nitrate M3 is used as a nitrating medium, it being possible for M to be the metals Fe, Cr, Y, La, Ce, Al, Bi and In, and the metal nitrate having a water content of from 4 to 9 mol of water per M3, leads to simplifications of the process and improved yields. The hub has an inner surface that surrounds an axis and defines a bore. The connection member is a permanent magnet which is attached to at least one of the column-shaped portion and the joining hole. Between the communications controllers, a communication path provides long distance communication via a packet-switched network. More particularly, it relates to pharmaceutical powder compositions having the content uniformity and the desired stability used in inhaler devices. , and more generally for the construction of several types of civil works; the module is essentially L-shaped having a long section and a short section substantially forming a right angle, the connection between them being reinforced by means of a bevel, and where the base of the long section is rough for increasing the friction with the soil.