Aims. We study the dependence of turbulent transport coefficients, such as α effect and turbulent magnetic diffusivity, on shear and magnetic Reynolds number in the presence of helical forcing. Methods. We use three-dimensional direct numerical simulations with periodic boundary conditions and measure turbulent transport coefficients using the kinematic test field method. In all cases the magne...

Compacted clay liners (CCLs) are the main materials used in waste disposal landfills due to their low permeability. In this study, the effect on the shear resistant of clays with inorganic salt solutions as permeate fluid was experimentally investigated. For this purpose, NaCl inorganic salt solution at concentrations of 2, 5, 10% and deionized water were used. Laboratory direct shear and Vane ...

The development of technologies that could be used by the U.S. beef packing industry to accurately characterize beef for tenderness has been a major focus of this laboratory. Because longissimus comprises a higher proportion of total carcass value than any other muscle and there is more carcassto-carcass tenderness variation in longissimus than any other major beef muscle (Shackelford et al., 1...

Vascular remodeling under conditions of growth or exercise, or during recovery from arterial restriction or blockage is essential for health, but mechanisms are poorly understood. It has been proposed that endothelial cells have a preferred level of fluid shear stress, or 'set point', that determines remodeling. We show that human umbilical vein endothelial cells respond optimally within a rang...

Using discrete element methods, geotechnical engineers can create “virtual laboratories” to simulate conventional laboratory tests. In this study, three-dimensional DEM simulations of direct shear tests are coupled with equivalent physical tests on steel balls. The macro-scale response of simulations is compared with the physical test results to validate the discrete element model and to gain i...

The prediction quality of discrete element method (DEM) models for railway ballast can be expected to depend on three points: the geometry representation of the single particles, the used contact models and the parametrisation using principal experiments. This works aims at a balanced approach, where none of the points is addressed with excessive depth. In a first step, a simple geometry repres...

Shear-induced cross-correlations of particle fluctuations perpendicular and along streamlines are investigated experimentally and theoretically. Direct measurements of the Brownian motion of micron-sized beads, held by optical tweezers in a shear-flow cell, show a strong time asymmetry in the cross-correlation, which is caused by the non-normal amplification of fluctuations. Complementary measu...

Phenomena such as shear thinning and thickening, occurring when complex materials are exposed to external forces, are generally believed to be closely connected to changes in the microstructure. Here, we establish a direct and quantitative relation between shear thinning in a colloidal crystal and the surface area of the locally melted region by dragging a probe particle through the crystal usi...

For flexible robots with rotational joints it has been shown previously, by the first author, that direct strain feedback can damp out vibrations very satisfactorily. In this paper, a simple sensor-based output feedback control law, called shear force feedback, is newly proposed to control vibrations arising from structural flexibility of robots of Cartesian or SCARA types. Closed-loop exponent...

The focal location of atherosclerosis in the vascular tree is correlated with local variations in shear stress. We developed a method to induce defined variations in shear stress in a straight vessel segment of a mouse. To this end, a cylinder with a tapered lumen was placed around the carotid artery, inducing a high shear stress field. Concomitantly, regions of low shear stress and oscillatory...