BACKGROUND Mechanical stresses are known to play important roles in atherosclerotic plaque initiation, progression and rupture. It has been well-accepted that atherosclerosis initiation and early progression correlate negatively with flow wall shear stresses (FSS). However, mechanisms governing advanced plaque progression are not well understood. METHOD In vivo serial MRI data (patient follow...

the efficiency of a collar in reducing the scour depth around circular and rectangular piers is studied at different flow intensities (ratio of upstream shear stress to sediment critical shear stress). rectangular piers aligned with the flow as well as skewed at 5º, 10º, 20º were examined. previous studies had shown that with collar the equilibrium time of scouring increases considerably. to re...

We have obtained data on the frequency of aggregates of different size classes and on the maximum aggregate diameter of lymphoid cells subjected to aggregation in the laminar shear field of a Couette viscometer. Maximum aggregate diameter reached a plateau level during aggregation. This plateau is considered to be the result of a balance between the hydrodynamic shear forces tending to resist t...

in this study, friction stir spot welding (fssw) is applied to join the tial6v4 titanium alloy with 1.5 mm thickness and then the effect of rotational speed and tool dwell time on microstructure and mechanical properties is investigated. in this regard, the speed of the tool rotation was considered as 800, 1000, and 1200 rpm, as well as the tool dwell time was set at 7 and 12s. microstructural ...

We have previously observed that von Willebrand factor (vWF) plays an important role in platelet deposition on subendothelium at low values of wall shear rate (200 to 400 seconds-1). In the present study, we have investigated the mechanism responsible for such a defect in platelet deposition at low shear rates in the absence of vWF. Blood from both normal and von Willebrand's disease (vWD) anim...

Joint connection methods, such as shear key and loop bar, improve the structural performance of precast concrete structures; consequently, there is usually decreased workability or constructional efficiency. This paper proposes a high-efficiency skewed pipe shear connector. To resist shear and pull-out forces, the proposed connectors are placed diagonally between precast concrete segments and a...

in this work, for the first time, the rheological properties of nanofluids of lanthania nanoparticles (nps) in ethylene glycol (eg) as functions of shear rate, volume fraction, and temperature were measured. the results showed that both eg and the nanofluids behave as non-newtonian fluids at lower shear rates and transform to newtonian fluids at higher shear rates. the values of viscosity for b...

The structural integrity of precast concrete buildings depends mainly on the connections between the precast structural components. Large precast concrete panels are used extensively in North America for low, medium, and highrise construction due to their ease and speed of assembly, and high quality control. This paper presents the results of twenty-two prototype specimens tested to investigate...

In continuing the investigation of AAA hemodynamics, unsteady flow-induced stresses are presented for pulsatile blood flow through the double-aneurysm model described in Part I. Physiologically realistic aortic blood flow is simulated under pulsatile conditions for the range of time-average Reynolds numbers 50< or =Re(m) < or =300. Hemodynamic disturbance is evaluated for a modified set of indi...

Shape memory alloys (SMAs) are unique smart materials that have many advantages, such as ability to resist large strains without leaving residual strains and ability to recover original form. However, the high costs of SMAs have limited their usage. This paper evaluates the behavior of concrete structures equipped with SMAs in an optimal manner as they are being used along the plastic hinge of ...