The network of forces between contacts in a granular material determines the response of the material to an external perturbation. As the shear stress is increased, a static, rigid material can start to yield and flow as it becomes unjammed. The time- and ensemble-averaged distribution of forces shows a marked change in character at this jamming-unjamming transition. Here, we investigate the te...

Polymers exposed to shear flow exhibit a remarkably rich tumbling dynamics. While rigid rods rotate on Jeffery orbits, a flexible polymer stretches and coils up during tumbling. Theoretical results show that in both of these asymptotic regimes the corresponding tumbling frequency f(c) in a linear shear flow of strength γ scales as a power law Wi(2/3) in the Weissenberg number Wi = γτ, where τ i...

This paper studies a steady axisymmetric flow in a constricted rigid tube. A shear-thinning fluid modelling the deformation-dependent viscosity of the blood is proposed. The motion equation is written in vorticity-streamfunction formulation and is solved numerically by a finite difference scheme. The flow pattern with the distributions of pressure and shear stress at the wall are computed. The ...

The large cellular volume of erythrocytes and the increased plasma concentration of proteins in elephants are factors which potentially affect blood rheology adversely. To verify blood rheology, routine hemorheologic variables were analyzed in four African elephants (Loxodonta africana), housed in the zoo of Vienna. Whole blood viscosity at three different shear rates (WBV at low shear rate: WB...

large panel precast structures are analyzed based on the connection rigidity. however, the connections undergo nonlinear and inelastic response, when subjected to seismic loads. thus, to study the actual behavior of structure, the connection nonlinearity should be implemented in the joints. in this paper, three conventional connection types are modeled based on the envelope of their cyclic resp...

We explore how a frozen background metric affects the mechanical properties of planar membranes with a shear modulus. We focus on a special class of "warped membranes" with a preferred random height profile characterized by random Gaussian variables h(q) in Fourier space with zero mean and variance <|h(q)|(2)>~q(-d(h)) and show that in the linear response regime the mechanical properties depend...

The shear response of soft solids can be modeled with linear elasticity, provided the forcing is slow and weak. Both of these approximations must break down when the material loses rigidity, such as in foams and emulsions at their (un)jamming point - suggesting that the window of linear elastic response near jamming is exceedingly narrow. Yet precisely when and how this breakdown occurs remains...

Thermodynamic expressions are derived for the system relative Gibbs free energy, and the relative Gibbs free energy per bubble, for all possible equilibrium bubble states that can form in a soft slightly rigid material, initially supersaturated with a dissolved inert gas (N(2)). While the thermodynamic manipulations are exact, the final expressions are approximate, due to an approximation made ...

Amorphous materials exhibit peculiar mechanical and vibrational properties, including non-affine elastic responses excess states, i.e., the so-called boson peak. For polymer glasses, these properties are considered to be affected by bending rigidity of constituent chains. In our recent work [Tomoshige, et al., Sci. Rep. 9 19514 (2019)], we have revealed simple relationships between variations g...

We have measured the rheological properties of individual red blood cells from fishes inhabiting different thermal environments and have also investigated the effects on red cells of acute in vitro temperature changes. The membrane shear elastic modulus (rigidity) increased markedly with decreasing temperature, and the dependence was similar if temperature was varied acutely in vitro or if cell...