Food includes a wide range of biological materials with diverse rheological character. They are mostly a mixture of different structures previously treated in this book: emulsions, suspensions, foams, gels, solutions and melts. This means that the food rheologist deals with complex fluids which often are substantially inhomogeneous. The variability in the biological food systems is large in con...

We formulate the thin-film hydrodynamics of a suspension of polar self-driven particles and show that it is prone to several instabilities through the interplay of activity, polarity, and the existence of a free surface. Our approach extends, to self-propelling systems, the work of Ben Amar and Cummings [Phys. Fluids 13 1160 (2001)10.1063/1.1359748] on thin-film nematics. Based on our estimates...

Electrorheological (ER) materials are suspensions of micron sized particles in insulating, dielectric fluids. The mechanical properties of these materials can be controlled by regulating an electric field through them. Variable properties include stiffness, damping, and yielding behavior. At high electric fields, material property changes are rapid and immediately reversible. ER technology has ...

Nanofluids are suspensions of nanoparticles in base fluids, a new challenge for thermal sciences provided by nanotechnology. Nanofluids have unique features different from conventional solid-liquid mixtures in which mm or μm sized particles of metals and non-metals are dispersed. Due to their excellent characteristics, nanofluids find wide applications in enhancing heat transfer. Research work ...

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau...

We study dense colloidal crystals under oscillatory shear using a confocal microscope. At large strains the crystals yield and the suspensions form shear bands. The pure harmonic response exhibited by the suspension rules out the applicability of nonlinear rheology models typically used to describe shear banding in other types of complex fluids. Instead, we show that a model based on the coexis...

Self-sustained turbulent structures have been observed in a wide range of living fluids, yet no quantitative theory exists to explain their properties. We report experiments on active turbulence in highly concentrated 3D suspensions of Bacillus subtilis and compare them with a minimal fourth-order vector-field theory for incompressible bacterial dynamics. Velocimetry of bacteria and surrounding...

The observation of localized stationary structures, coined oscillons, in granular media has evoked much interest. By parametric excitation of clay suspensions, we demonstrate a hysteretic transition to oscillon-type states in a nongranular medium. When the symmetry of up-down reflection 1 time translation is lost, these states undergo a transition to propagating localized states previously seen...

This is the second in a series of articles describing a wide variety of projects at NIST that synergistically combine physical science and information science. It describes, through examples, how the Scientific Applications and Visualization Group (SAVG) at NIST has utilized high performance parallel computing, visualization, and machine learning to accelerate research. The examples include sci...

The cytopathic effect of lymph node cells from tuberculin-sensitized rats on rat embryo fibroblasts in the presence of PPD was not enhanced by admixture of normal (nonsensitized) lymph node cells. Preincubation studies showed that this in vitro response is initiated by the reaction of lymphocytes with specific antigen, beginning within 30 min, rather than uptake of antigen by the fibroblasts. T...