Palladium catalysed cyclisation-carbonylation of enynes to give cyclic gamma,delta-unsaturated acids

In the presence of acetic acid, trifurylphosphine and CO (2 atm), palladium catalyses the conversion of a range of enynes to cyclic delta,gamma-unsaturated carboxylic acids in good yield.     

Acetylation of aromatic ethers using acetic anhydride over solid acid catalysts in a solvent-free system. Scope of the reaction for substituted ethers

The acetylation of aryl ethers using acetic anhydride in the presence of zeolites under modest conditions in a solvent-free system gave the corresponding para-acetylated products in high yields. The zeolite can be recovered, regenerated and reused to give almost the same yield as that given when fresh zeolite is used.     

Materialgleichungen zur beschreibung des primären kriechverhaltens innendruckbeanspruchter zylinderschalen aus isotropem werkstoff

Übersicht Zur Beschreibung des primären Kriechverhaltens metallischer Werkstoffe werden tensoriell nichtlineare Materialgleichungen vorgeschlagen. Diese werden in Verbindung mit der Dehnungsverfestigungshypothese der Untersuchung des Deformationsverhaltens inn endruckbeanspruchter dünnwandiger Kreiszylinderschalen zugrunde gelegt.

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Constitutive equations describing the primary creep behaviour of isotropic cylindrical shells subjected to internal pressure

Summary In order to describe the creep behaviour of metals in the primary stage tensorial non-linear constitutive equations are proposed involving the strain-hardening hypothesis. Based upon these general relations the primary creep behaviour of a thin-walled circular cylindrical shell, subjected to internal pressure, is analysed.