Stress interfaeial

Figures 32 and 33 show the fully eorreeted plots of shear stress versus shear rate. Taking aeeount of small differenees in the measured interfaeial tensions, all data eould be aeeu-rately represented by...

There are four rheologieal parameters which describe the response to imposed interfaeial stresses or deformation. For a Newtonian interfaee, the signifieant rheological properties that determine interfaeial motion are the interfacial shear viscosity, the interfaeial dilational viscosity, and the interfaeial tension gradient. The interfaeial shear elasticity, e and viscosity, describe the resistance of the... 

They adapted an interfacial shear rheometer (plate/ rod) to measure the shear viscoelasticity of the system with and without dispersant. At an applied shear stress, creep curves for the system were monitored. There were no instantaneous elasticity and viscosity for the Kuwait and Tia Juana crudes with and wifliout dispersant. They attributed this to a network structure of flocculated asphaltenes in the films. They found that there was some dilatancy in their crude oil films, described as a stick/slip flow in their flow curves. However, fliis flow was attributed to thick films of asphaltene particles building up at the interface. Lfsing creep measurements, they examined a model system of as-phaltenes/n-heptane/toluene. They found a retarded elastic deformation, which was different from the response of the crade oils. This suggested to fliem that there was a different type of interfaeial slrueture formed with the model oil, and this may be attributed to die solveney of the medium and not to die lower asphaltenes eontent in the model system. 

Melcher, J. R. and Taylor, G. I. Eleetrohydrodynamies A review of the role of interfaeial shear stresses. Annual Review of Fluid Mechanics, 1, 111-146 (1969). 

All the relevant interfaeial quantities can be expressed as integrals over the three-dimensional pressure tensor P of the interface regarded as a three-dimensional body. The pressure tensor is simply the negative of the three-dimensional mechanical stress tensor tr (to be distinguished from the two-... 

Aramid fibers were subjeeted to a variety of surfaee treatments to improve the interfaeial stress transfer between a thermoplastie matrix and the treated fiber eomposite. Analytical techniques to characterize the effect of surface treatment included DSC, Optical Microscopy, AFM and micromechanical analysis using Raman spectroscopy. Correlations between the different analysis methods were identified. It was found that plasma modified and chloride grafted fibers had the largest degrees of transcrystallinity, highest nucleation rates and greatest interfaeial shear strength between fiber and matrix. 

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