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For developing a new composite material owning shear-thickening characteristic, the rheological behaviors of nano-sized precipitated calcium carbonate (PCC) particles with irregular sharp in glycerine were investigated systematically by means of steady and dynamic rheometry. The results showed that the concentrated PCC suspensions exhibit a strong shear-thickening behavior under both steady and dynamic oscillatory shear when the volume fraction of PCC above the threshold (about 41%). In steady shear tests, the critical shear rate decreases and the maximum viscosity in shear thickening region increases dy namically with the increase of volume fraction. While, for suspensions with different volume fractions, the similar critical stress for the onset of shear thickening is found. In dynamic strain sweep at different fixed frequencies, with the increase of fixed frequency, the complex viscosity of suspensions decreases slightly, while the critical strain for shear-thickening shifts to lower value. The dynamic oscillatory rheological behavior of suspensions at low frequency (ω < 100 rad/s) could be reasonably interpreted in terms of the steady shear behavior. For the suspensions with same volume fraction, it was interestingly found that the critical dynamic shear rate equaled to the product of critical strain and frequency could agree well with the critical shear rate in steady shear. Moreover, the rheological behavior of PCC suspensions shows excellent reversibility and reproducibility.

The rheological behavior of oilfield surfactants (Aromox ® APA-T and APA-TW) at various concentrations was studied using steady shear and dynamic testing. The results showed that the solutions exhibit non-Newtonian behavior at all concentrations, with their rheological character influenced by the temperature and ionic content of the base fluid. Temperature was observed to have a significant effect on viscosity and dynamic data. The apparent viscosity at different temperatures could be reduced to a single master curve using horizontal and vertical shift factors. However, satisfactory scaling could not be attained for the dynamic or viscoelastic data. Molecular scaling using characteristic time for data at different concentrations proved unsuccessful due to the strong non-Newtonian character of surfactant solutions. Scaling relations between rheological parameters and concentration indicated the presence of long micelles in APA-T solutions. APA-TW solutions, on the other hand, contained branched micelles.

A Sentmanat Extension Rheometer represents one out of a few experimental devices for the measurement of elongational viscosity of polymer melts. However, the appropriateness of this technique for individual polymer materials is not sufficiently apparent and in some case is disregarded or ignored. The proposed visualization technique is based on imprinting painted pattern from the inner surface of the studied polymer samples onto the counter-rotating drums. Digitization of the imprinted pattern gives a possibility to evaluate a degree of sagging, incorrect fixing of rectangular polymer samples to the drums, possible appearance of sample inhomogeneity (variance in thickness, bubbles, etc.). The presented visualization technique is demonstrated using branched LDPE Escorene. Two various imprinted patterns are applied. First, the upper and lower contours are charted on a prepared sample with the aim to determine the sample shapes during stretching and to compare them with the theoretical ones. Second, the inclined rectangular grid pattern is charted for evaluating possible inhomogeneity of the sample.

An elasto-visco-plastic model of the Cauchy stress is proposed for gluing solution of railway ballast, with an asymptotic timedependent viscosity accounting for the anti-thixotropic and shear-thickening features. Flow characteristics and time-dependent solidification of the gluing solution in the multiconnected conducts spanned by the gravels, accomplished by the algorithm in generating a ballast consisting of convex octahedral grains, are simulated by using the ANSYS © package. While different vertical penetrations of the gluing solution can be achieved by using different characteristic times scales of the asymptotic time-dependent viscosity, the lateral extension is rather limited and local. Pouring gluing solution into ballast tends to create more concrete adhesion between the gravels vertically, while concrete lateral adhesion can be obtained by spreading gluing solution onto ballast. The present study provides an integrated method for the estimation of the gluing solution distribution in a ballast, and for optimal layout of the gluing solution arrangement a priori gluing practice.