We study the rheology and distribution of interparticle contact lifetimes for gravity-driven, dense granular flows of noncohesive particles down an inclined plane using large-scale, three dimensional, granular dynamics simulations. Rather than observing a large number of long-lived contacts as might be expected for dense flows, brief binary collisions predominate. In the hard-particle limit, th...

We present high spatial resolution, near-IR images in J,H, and K of the nucleus of NGC 3227, obtained with the Adaptive Optics bonnette on CFHT. The 0:15" (17pc) resolution allows us to probe structures in the very core region at unprecedented scales. We are able to identify an inwards spiraling starburst in all three near-IR bands and a counterpart in an HST V-band image. Dust obscuration beco...

Standards have limited the allowable noise levels in different situations, requiring the study of solutions at the source, in the path or the receiver. Muffler is the major factor influencing the noise of rotary compressor. Control and analyze the acoustic characteristics of muffler is essential. Porous materials have been studied and widely applied to reduce aircraft and vehicular noise or ind...

When a solid sphere drops in a granular medium, an impact crater is created. The penetration of the projectile in the granular bed as a function of the impact energy is evaluated theoretically using a simple model including a friction law between the projectile and the grains, a viscous dissipation in the bed and a force from the collisions between the projectile and the granular material. This...

We study the impact and subsequent retraction dynamics of liquid droplets upon highspeed impact on hydrophobic surfaces. Performing extensive experiments, we show that the drop retraction rate is a material constant and does not depend on the impact velocity. We show that when increasing the Ohnesorge number, Oh = η/ √ ρRIγ, the retraction, i.e. dewetting, dynamics crosses over from a capillaro...

Gas flow and performance characteristics of a high-temperature micro-electronically machined systems (MEMS)-based thruster are studied using a coupled thermal-fluid analysis. The material thermal response governed by the transient-heat-conduction equation is obtained by the finite element method. The low–Reynolds number gas flow in the microthruster is modeled by the direct simulation Monte Car...

Abstract. A numerical solution is presented for unsteady coupled heat and mass transfer by natural convection from a non-Newtonian power-law fluid flow past a vertical plate embedded in a non-Darcian porous medium in the presence of viscous dissipation and chemical reaction effects. The governing equations are formulated and a numerical solution is obtained by using an explicit finite-differenc...

As reported by earlier investigators, the epithelium of the digestive tubules is composed of two cell-types. One type of cell is glandular, the other type is absorptive and digestive, and to a lesser extent secretory. The latter type of cell also contains glycogen and numerous lipid globules, so that the digestive gland as a whole contains a large quantity of reserve food material. The epitheli...

Experiments in quasi-two-dimensional geometry (Hele-Shaw cells) in which a fluid is injected into a viscoelastic medium (foam, clay, or associating polymers) show patterns akin to fracture in brittle materials, very different from standard Laplacian growth patterns of viscous fingering. An analytic theory is lacking since a prerequisite to describing the fracture of elastic material is the solu...

Understanding glass formation is a challenge, because the existence of a true glass state, distinct from liquid and solid, remains elusive: Glasses are liquids that have become too viscous to flow. An old idea, as yet unproven experimentally, is that the dynamics becomes sluggish as the glass transition approaches, because increasingly larger regions of the material have to move simultaneously ...