BACKGROUND AND PURPOSE Realistic, population based cerebrovascular replicas are required for the development of neuroendovascular devices. The objective of this work was to develop an efficient methodology for manufacturing realistic cerebrovascular replicas. MATERIALS AND METHODS Brain MR angiography data from 20 patients were acquired. The centerline of the vasculature was calculated, and g...

In the presented work, sulfur concrete and rubber were used for producing functionally graded materials (FGM). The physical and mechanical properties of sulfur concrete and rubber were changed continuously across the thickness. On one side, there was just rubber and, on the other, there was pure sulfur; the properties of each substance were moved to reach another. This kind of material was cons...

This article describes fretting behavior of zirconia and silicon nitride balls on an electro-deposited coating. Fretting tests are performed using a ball-on-flat configuration. The evolution of the kinetic friction coefficient is determined, along with slip ratio. Experimental results show that the steady-state friction coefficient between ceramic balls (Si₃N₄ and ZrO₂) and an electro-deposited...

In the discrete element simulation of granular materials, the modelling of contacts is crucial for the prediction of the macroscopic material behaviour. From the tribological point of view, friction at contacts needs to be modelled carefully, as it depends on several factors, e.g. contact normal load or temperature to name only two. In discrete element method (DEM) simulations the usage of Coul...

Based on the classical regression model, timevarying coefficient model, unit root, co-integration, Granger causality test, VAR, impulse response and variance decomposition, the dynamic relationship between prices of natural rubber futures in China and Japan has been researched systematically. The following conclusions are gotten through empirical researches: Firstly, there is a stable co-integr...

Cf = skin friction coefficient CD = drag coefficient CDf = friction drag coefficient CDp = pressure drag coefficient h = step height M0 = freestream Mach number Patm = atmospheric pressure Pi = stagnation pressure Re = freestream Reynolds number Ti = stagnation temperature U = velocity U = normalized velocity Uτ = friction velocity X = longitudinal coordinate Z = vertical coordinate Z = normali...

one of the main factors that cause to quality loss for fresh fruit market apples is bruise damage. amongst the factors that affect apple sensitivity to bruising, major one is drop height and area profile during the impact. in the present study, four iranian apple varieties consisted of atirli, kapak, kowse and paiez that were selected and 100 fruits of each variety were picked up, then apples w...

tan films with different n2 partial pressure were deposited on 304 stainless steel using the magnetron sputtering method. the effect of gas pressure on the mechanical property, morphology and phase structure of the films is investigated by x-ray diffraction (xrd), atomic force microscopy (afm), microhardness testing, friction coefficient measurements, and wear mechanism study. the xrd results c...