High pressure transport behaviour of AgI-Ag2O-MoO3 glasses and the cluster model

The effect of pressure on the conductivity of fast ion conducting AgI-Ag₂O-MoO₃ glasses has been investigated down to 150 K. The observed variation of conductivities appears to support the application of cluster model to the ionic glasses. Contribution No. 258 from the Solid State and Structural Chemistry Unit.     

The non-isothermal rheological behaviour of molten polymers: Shear and elongational stress growth of polyisobutylene under heating

Summary Data of stress growth under both shear and elongational kinematics have been taken in presence of heating temperature ramps on a commerical polyisobutylene.The experimental results have been analysed on the basis of a generalized Maxwell model already proved to be very accurate in predicting the isothermal behaviour. A good agreement is observed between the theoretical predictions and the experimental results.Also the features usually observed in volume-temperature curves by effect of cooling acrossT _g are qualitatively reproduced by the model.With 6 figures     

Rheological properties of paraffin suspensions of surface-modified alumina powder for low-pressure injection moulding

Due to the hygroscopic nature of fine alumina powders, the presence of water may have a detrimental effect on the rheological properties of a suspension in melted paraffin for low-pressure injection moulding (LPIM). For this reason, a modification of the powder surface from hydrophilic to hydrophobic is essential for the production of high-quality moulded ceramics. In our paper, the efficiency of the application and the chemisorption of protective monomolecular layers of a long-chain carboxylic acid or its salts will be presented. The effect of the powder treatment on the shear viscosity and the viscoelastic properties of the suspensions for LPIM as well as on their stability in terms of the detrimental effect of water will be discussed.This paper was presented at the first Annual European Rheology Conference (AERC) held in Guimarães, Portugal, September 11-13, 2003.     

Thermal behaviour of complexes of antipyrine derivatives II

Parent and mixed ligand complexes of cobalt(II) and copper(II) ions with N,N-bis-(4-antipyrylmethyl)piperazine or N,N-tetra(4-antipyryl-methyl)-1,2-diaminoethane or/and imidazole as ligand and ClO ₄ ^– or SCN^– as counterion were synthesised and their thermal behaviour was investigated.This work was performed in the framework of cooperation between the Hungarian Academy of Sciences and Romanian Academy and was supported financially, in part, by the Hungarian Scientific Research Foundation (OTKA T 029554).     

Polyacid gels under a uniaxial load

Swelling and shrinking of polyacid gels is accompanied by forming and breaking of hydrogen bonds yielding additional crosslinks of the polymer network. Continuous forming and breaking of hydrogen bonds even in equilibrium gives rise to viscoelastic behaviour. Based on molecular considerations a two-network model has been developed to describe microstructural changes under a uniaxial load. A phenomenological theory is presented which describes the temporal evolution of viscoelastic processes. By this approach the number of adjustable parameters can be reduced considerably compared to the Kelvin or Maxwell model.Received: 11 November 2002, Accepted: 10 February 2003, Published online: 27 June 2003     

Combustion Behaviour of Nitrocellulose and its Complexes with Copper Oxide. Hot stage microscopic studies

Complexes of nitrocellulose (NC – low and high nitrogen content) with copper oxide (CuO) have been synthesized and studied for morphological behaviour on heating from room temperature to 500°C with the help of hot stage microscopy (HSM). During decomposition, NC:CuO complexes show contraction of fibrous boundaries followed by mass movement of matrix, with the evolution of brown yellow colour gas at higher temperatures as compared to NC alone. This revised version was published online in July 2006 with corrections to the Cover Date.     

Oscillation of Forced Nonlinear Neutral Delay Difference Equations of First Order

Necessary and sufficient conditions are obtained for every solution of

On oscillation and asymptotic behaviour of solutions of forced first order neutral differential equations

In this paper, sufficient conditions have been obtained under which every solution of