Abstract: In the preparation of ammonium carbamate by reacting ammonia with carbon dioxide, the reactants are introduced into a layer of ammonium carbamate which is kept in the fluidized state by gaseous ammonia or carbon dioxide. The temperature is kept below 25.degree. C. by removing the heat of reaction.

Abstract: For the purpose of monitoring the formation and propagation of cracks in machine parts and components, especially in the rotating shafts of prime movers and mechanical equipment, at least one hole is drilled in the uncracked section of the component, this drilled hole intersecting the plane of the crack which is to be expected and being filled with a gas or a liquid, the gas or liquid being adjusted to a pressure above the ambient pressure, and the drilled hole being provided with a closure with respect to the environment and being connected, via a line, to an instrument for indicating a fall in the pressure of the medium present in the drilled hole.

Abstract: A process and apparatus for removing suspended matter from suspensions by filtering through foams, in which the suspended matter retained in the foam (polyurethane foam produced by foaming with water vapor being preferred) is substantially flushed out by expressing the liquid held in the foam, and is removed as a concentrate. This for the the first time permits the removal of suspended matter from continuously flowing suspensions without the flow of the suspensions having to be interrupted in order to clean the filtering means.