Abstract: Copolymers, desirably having a molecular weight of from 500 to 20000, of aminoesters or aminoamides of (meth)acrylic acid and (meth)acrylamides at a molar ratio of from 10:1 to 60:1, particularly from 12:1 to 50:1 and especially about 20:1, can act as gas hydrate inhibitors in water containing hydrocarbon gas streams. Desirably the aminoesters or aminoamides are N-alkyl-amino(esters or amides) in particular of the formula (I): H2C?CR1 C(O)XR2NR3R4 (I) where R1, R2, R3, R4 and X have defined meanings and the (meth)acrylamides are of the formula (II): H2C?CR6C(O)NR7R8 (II) where R6, R7 and R8 have defined meanings. Methods of treating gas water mixtures using the copolymers to inhibit gas hydrate formation are described.

Abstract: An improved fastener system is derived for cold working the surfaces defining aligned fastener holes in structural members and installing fasteners therein. Essentially, an integral fastener and mandrel construction facilitates the insertion of a sleeve into the holes, an expansion of the sleeve thus disposed to thereby cold work the surfaces of the members defining the holes, and the pulling of the fastener into the holes thus prepared and sleeve-lined. A frangible neck is provided between the fastener element and the mandrel element which permits the breaking off and discarding of the latter after the former is installed. Retenion means is then installed, formed or otherwise provided on the fastener end in conventional manner. Thus, cold working and fastener installation is accomplished in only two steps due to the critical design and configuration of the combined fastener, break-off groove and mandrel.