AIM This study aimed to test the accuracy of a speckle tracking algorithm to assess myocardial deformation in a large range of heart rates and strain magnitudes compared to sonomicrometry. METHODS AND RESULTS Using a tissue-mimicking phantom with cyclic radial deformation, radial strain derived from speckle tracking (RS-SpT) of the upper segment was assessed in short axis view by conventional...

In this study, the performance of a centrifugal pump is investigated by adding polyacrylamide (PAM) polymer over the working fluid which is tap water in this case. PAM is a long chain polymer that leads to reduce the wall shear stress and drag in a turbulent fluid. Three different blade profiles including radial, straight backward and circular backward have been examined. For this purpose, a ce...

Stress alters brain cell properties and then disturbs cognitive processes, such as learning and memory. In this study, we investigated the effect of postnatal treadmill exercise on hippocampal neurogenesis and spatial learning ability of rat pups following prenatal noise stress. The impact of exercise intensity (mild-intensity exercise vs heavy-intensity exercise) was also compared. The pregnan...

This study is focused on finite element analysis of a model comprising femur into which a femoral component of a total hip replacement was implanted. The considered prosthesis is fabricated from a functionally graded material (FGM) comprising a layer of a titanium alloy bonded to a layer of hydroxyapatite. The elastic modulus of the FGM was adjusted in the radial, longitudinal, and longitudinal...

The present study aims at investigating stress and deformation behavior of rotating thick truncated conical shells subjected to variable internal pressure. Material prpperties of the shells are graded along the axial direction by Mori-tanaka scheme, which is achieved by elemental gradation of the properties.Governing equations are derived using principle of stsionary total potential (PSTP) and ...

removal of the radial artery for myocardial revascularization: a Doppler study to prevent ischemic complications to the hand. Assessment of the radial artery and hand circulation by computed tomography angiography: a pilot study. According to your study w1x, one of the contraindications for radial artery harvesting is its small inner proximal and distal diameter, smaller than 2 mm (Tables 2 and...

Pitting corrosion is one of the most common forms of localized corrosion. Corrosion pit results in a stress concentration and fatigue cracks usually initiate and propagate from these corrosion pits. Aging structures may fracture when the fatigue crack reaches a critical size. This paper experimentally simulates the effects of pitting morphologies on the static and fatigue behavior of steel bars...

0266-3538/$ see front matter 2011 Elsevier Ltd. A doi:10.1016/j.compscitech.2011.01.009 ⇑ Corresponding author. E-mail address: [email protected] (G.J. Nie). We present a technique to tailor materials for functionally graded (FG) linear elastic hollow cylinders and spheres to attain through-the-thickness either a constant hoop (or circumferential) stress or a constant in-plane shear stress. The...

This paper mainly studies the behavior of axisymmetric radial interaction between soil and structure under stress. Considering possible factors in interaction, such as arching effect caused by finite curvature, a simplified model is established. The influence curvature change on stress field, strain displacement field stress-strain relationship analyzed. Finally, status various their changes ar...