We sought to determine whether intermittent short-duration exposure to low wall shear stress could induce intimal thickening in arteries chronically exposed to high shear stress. An arteriovenous fistula (AVF) was created between the left common carotid artery and the corresponding external jugular vein in 20 Japanese white male rabbits. After 4 weeks, blood flow was increased 10-fold to 182 +/...

The fluctuating wall shear stress, wall pressure, and streamwise velocity were measured simultaneously in a cylindrical boundary layer at a momentum thickness Reynolds number of Reu52160 and a boundary layer thickness to cylinder radius ratio of d/a55 using a hot wire wall shear stress probe mounted just upstream of a hearing aid microphone and a hot wire velocity probe. Variable Interval Time ...

Current knowledge of the mechanics of alluvial channels depends very largely on calculations of turbulent shear stresses; typical examples are the beginning of motion of sediment particles and sediment transport in alluvial channels. If shear stress can be well defined in clear-water flows, comparatively little is known about shear stresses in sediment-laden flows. Einstein and Chien (1955) pro...

Shear stress modulates gene expression in endothelial cells (ECs) partly through nitric oxide (NO), acting via enhanced cGMP formation by guanylyl cyclase (GC). We addressed non-cGMP-mediated transcriptional responses to shear stress in human umbilical ECs subjected to high-laminar shear stress (25 dyn/cm2; 150 minutes). RNA was isolated, reverse-transcribed, Cy3/5-labeled, and hybridized to 19...

Vascular endothelial cells are potent modulators of vascular tone in response to shear stress. Levels of vasoactive peptides such as adrenomedullin (AM), endothelin-1 (ET-1), C-type natriuretic peptide (CNP), and nitric oxide (NO) are affected by fluid shear stress. AM, a potent vasodilator and suppressor of smooth muscle cell proliferation, contains the shear stress responsive element (SSRE) "...

We examine the SI effects and Bachman’s SI Parameterization in a two-fronts LES simulation. The domain, governed by periodic horizontal temperature profile, consists of a Geostrophic Stable front and a Geostrophic Unstable front. In the study, we find that the Bachman’s SI Parameterization is not good enough to reproduce the Reynolds stress and the SI turbulent buoyancy transport in the LES sim...

Transient finite coupled thermomechanical simple shearing deformations of a block made of an elastothermoviscoplastic material that exhibits strain and strain-rate hardening, and thermal softening are studied by using the meshless local Bubnov–Galerkin method. A local nonlinear weak formulation and a semidiscrete formulation of the problem are derived. The prescribed velocity at the top and the...

physical modeling for study of deep foundations can be performed in simple chambers (1g), calibration chambers (cc), and centrifuge apparatus (ng). these common apparatus face certain limitations and difficulties. recently, frustum confining vessels (fcv) have been evolved for physical modeling of deep foundations and penetrometers. shaped as the frustum of a cone, this device applies steady pr...

The dynamic and static yield stress of fresh cement mortar were measured in a rotational rheometer with a vane geometry using shear rate and shear stress-controlled protocols, respectively. Through a shear rate-controlled steady-state protocol, the equilibrium flow curve is measured and fitted with the Bingham model to obtain dynamic yield stress. A negative slope in the equilibrium flow curve,...