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Blood flow disturbance and wall shear stress parameters have been widely related to the onset and progression of atherosclerosis in the carotid artery. Assessment of these parameters can be performed using computational fluid dynamics (CFD) simulation in three-dimensional models derived from scans of a luminal cast has been used to investigate the blood flow in the carotid artery bifurcation of human beings, which known as the typical location for the formation of recirculation flow and low-oscillatory wall shear stress. This study utilized pulsatile and cyclic velocity profiles at the inlet boundary condition, while the outlet boundary condition is defined to be constant pressure, that is 100 mmHg. Since the blood is a non-Newtonian fluid, the viscosity coefficient of blood is not constant, but rather as a function of the velocity gradient. Therefore, we employ the Carreau model as blood viscosity. The CFD simulation has shown the localization of atherosclerosis is associated with the local hemodynamics parameter, as there are recirculation flow and low wall shear stress present at the carotid bifurcation, particularly at the near bifurcation and carotid sinus. [ABSTRACT FROM AUTHOR]

A prosthesis ankle-foot is an artificial replacement of a transtibial (below the knee) or transfemoral (above the knee) amputee for basic mobility. The aim of this study is to develop a passive prosthetic ankle-foot design and simulate the strength for transtibial or transfemoral that will support a more natural gait. Inspired by the role of the ankle-foot of an able-bodied gait, the compliant mechanism ankle-foot was designed. The design of the ankle-foot was obtained by the software SolidWorks. Then the strength analysis was done using ANSYS. The simulation was done with a walking gait cycle. Compared to existing prostheses, the novel prosthesis exhibits a greater and significantly different ankle than existing prostheses during gait. The compliant mechanism could improve the quality of life for a growing number of individuals living with limb loss in Indonesia and around Asia. The ankle-foot design in this study is new by developing existing designs so that the results are more flexible when used in walking conditions. The design is also adapted to Indonesian anthropometry so that it will further increase the comfort for prosthesis users in this country. [ABSTRACT FROM AUTHOR]

The texture shapes play a key role in the tribological performance of the surface material. This paper presents a study on the use of the 3D finite element method for surface stress analysis on the different texture shape under load and dry sliding contact. The five texture-shaped model was investigated in this work, namely square, circle, ellipse, triangle, and chevron. The result shown that the square shape has the highest value of von Mises resultant stress under static load. In contrast, the dry sliding contact on the triangle shape provided the highest von Mises stress distribution. The lowest value of von Mises stress can be found in the texture pattern of circle, square, and chevron under influence of load for 17 N, 30 N, and 50 N, respectively. Those texture patterns applied to surface of Ultra High Molecular Weight Polyethylene (UHMWPE) may have a strong effect on the reduction of wear rate and enhance tribological performance. [ABSTRACT FROM AUTHOR]