Propulsion of a bolus through the upper esophageal sphincter (UES) is driven by a pressure drop in the direction of flow against frictional resisting force. Basic mechanics suggest that the axial rate of drop in intrabolus pressure (IBP), i.e., the intrabolus pressure gradient (IBPG), should be locally sensitive to abnormal constriction. We sought to quantify space-time patterns of IBP and IBPG...

While frictionless spheres at jamming are isostatic, frictional spheres at jamming are not. As a result, frictional spheres near jamming do not necessarily exhibit an excess of soft modes. However, a generalized form of isostaticity can be introduced if fully mobilized contacts at the Coulomb friction threshold are considered as slipping contacts. We show here that, in this framework, the vibra...

Geckos use millions of adhesive setae on their toes to climb vertical surfaces at speeds of over 1 m s(-1). Climbing presents a significant challenge for an adhesive since it requires both strong attachment and easy, rapid removal. Conventional pressure-sensitive adhesives are either strong and difficult to remove (e.g. duct tape) or weak and easy to remove (e.g. sticky notes). We discovered th...

This paper presents a two-dimensional interface model for timber-concrete contacts, that has been developed based on the empirical observations from set of friction tests and additional micromechanical assumptions. In tangential direction, accounts initial bonding debonding between surfaces, different static kinetic as well smooth transition them, effects load reversal, pressure-dependence in s...

This paper aims to investigate the microscopic friction mechanism based on in situ microscopic observation in order to record the deformation and contact situation of friction lining during the frictional process. The results show that friction coefficient increased with the shear deformation and energy loss of the surfacee, respectively. Furthermore, the friction mechanism mainly included adhe...

Experimental studies implicate late systolic load as a determinant of impaired left-ventricular relaxation. We aimed to assess the relationship between the myocardial loading sequence and left-ventricular contraction and relaxation. Time-resolved central pressure and time-resolved left-ventricular geometry were measured with carotid tonometry and speckle-tracking echocardiography, respectively,...

[1] The dynamics of abyssal equator-crossing flows are examined by studying simplified models of the flow in the equatorial region in the context of reduced-gravity shallow water theory. A simple ‘‘frictional geostrophic’’ model for one-layer cross-equatorial flow is described, in which geostrophy is replaced at the equator by frictional flow down the pressure gradient. This model is compared v...

A comprehensive study of two-phase flow mechanisms and pressure drop in horizontal small hydraulic diameter tubes was conducted. Co-current flow of air-water mixtures in four round tubes and one rectangular tube with hydraulic diameters ranging from 5.5 mm to 1.3 mm were investigated. Bubble, dispersed, elongated bubble, slug, stratified, wavy, annular-wavy, and annular flow patterns were obser...

In automated layup manufacturing processes of fiber-reinforced polymer composites, the quality manufactured part is strongly dependent on frictional behavior. Improper control forces can lead to defect formation. Frictional sliding rheometry tests provide an innovative methodology accurately characterize tool-ply friction unidirectional (UD) prepreg employing unique annular plate geometries. Th...

The frictional behaviours between unsaturated soils and structure are controlled mainly by the complex phenomena that develop within a thin soil layer close to contact area. constitutive model for soil-structure interfaces (SSI) must be established predict performance of related soil-structuresystems accurately. Multi-stage suction-controlled ring shear (RS) tests with three different upper ann...