Abstract: A spring fastener, which comprises two engagement springs in opposite sides of the fastener. Each engagement spring has an engagement portion comprising a hindrance portion, which increases considerably the removal to insertion force ratio as compared to such ratio when the engagement portion does not have the hindrance portion, thus permitting very easy insertion into, with considerably more difficult removal of the fastener from the slot of a panel.

Abstract: Gases which are produced by the hydrogenolysis of hydrocarbons and which contain hydrogen, paraffins and aromatic compounds are contacted with a quenching medium such as a cooled fluidised bed or a cooled inert gas or liquid to cool the gas to a temperature lower than that which will support any substantial reaction between the hydrogen, paraffinic and aromatic constituents to produce carbonaceous compounds which will be deposited on the surfaces of reaction vessel or gas off-takes. Methane containing gases produced by the non-catalytic hydrogenolysis of oils with a hydrogenating gas at temperatures between 500.degree.-1000.degree.C may be quenched to a temperature not greater than 700.degree.C to prevent after reaction.