The interactions of blood flow with complex vessel geometry generate hemodynamic characteristics, including the heterogeneous spatial and temporal mechanical forces acting on the vessel wall. Vascular endothelial cells (ECs) covering the inner surface of blood vessels are constantly exposed to shear stress because of the frictional force created by the blood flow. ECs respond to the changes of ...

Shear rate is significantly lower in the superficial femoral compared with the brachial artery in the supine posture. The relative shear rates in these arteries of subjects in the upright posture (seated and/or standing) are unknown. The purpose of this investigation was to test the hypothesis that upright posture (seated and/or standing) would produce greater shear rates in the superficial fem...

OBJECTIVE Knee ligament injuries frequently cause devastating impairment to the injured. In car-pedestrian impact accidents, lateral-medial shear displacement is one of principal mechanisms of knee ligament injuries. The current study aims to investigate injury thresholds of knee ligaments under lateral-medial shear loading to improve pedestrian safety. METHODS Ten isolated human knee joints ...

The plastic flow of metallic glasses (MGs) in bulk is mediated by nanoscale shear bands, which is known to proceed in a stick-slip manner until reaching a transition state causing catastrophic failures. Such a slip-to-failure transition controls the plasticity of MGs and resembles many important phenomena in natural science and engineering, such as friction, lubrication and earthquake, therefor...

Miniature sensors that could measure forces applied by the fingers and hand without interfering with manual dexterity or range of motion would have considerable practical value in ergonomics and rehabilitation. In this study, techniques have been developed to use inexpensive pressure-sensing resistors (FSRs) to accurately measure compression force. The FSRs are converted from pressure-sensing t...

Nine restrained T-beams were tested in a study of the negative moment region shear strength of lightly reinforced concrete T-beams. Variables included the longitudinal reinforcement ratio p, (0.47 percent and 0. 70 percent) and the nominal stirrup strength (0 to 84 psi [0 to 0.60 MPa]). The test results are compared with the shear provisions of "Building Code Requirements for Reinforced Concret...

The nearshore potential vorticity balance of Bowen and Holman (1989) is expanded to include the forcing from wave group-induced radiation stresses. Model results suggest that the forcing from these radiation stresses can drive oscillations in the longshore current that have a spatial structure similar to linear shear instabilities of the longshore current. In addition, the forced response is ne...

The vascular endothelium is exposed to a spectrum of fluid mechanical forces generated by blood flow; some of these, such as fluid shear stress, can directly modulate endothelial gene expression. Previous work by others and in our laboratory, using an in vitro uniform laminar shear stress model, has identified various shear stress response elements (SSREs) within the promoters of certain endoth...

The present comprehensive physical and optical measurements have captured sediment resuspension associated with two hurricanes, Edouard and Hortense, that passed over the Coastal Mixing and Optics study site in the fall of 1996. Sediment resuspension associated with Hurricane Edouard was forced by combined current and wave processes. Combined current-wave bottom shear stresses exceeded 3.5 dyn ...

This paper analyzes the hydrodynamic and atmospheric instability modulation mechanisms which influence the Brazilian Current's (BC) thermal front signature in Synthetic Aperture Radar (SAR) images. Simulations were made using the M4S SAR imaging model. Two SAR images of the Brazilian Southeastern Coast depicting the BC's thermal front were selected including a VV (ASAR/Envisat) and a HH polariz...