PURPOSE To evaluate whether a non-linear blood ΔR2*-versus-concentration relationship improves quantitative cerebral blood flow (CBF) estimates obtained by dynamic susceptibility contrast (DSC) MRI in a comparison with Xe-133 SPECT CBF in healthy volunteers. MATERIAL AND METHODS Linear as well as non-linear relationships between ΔR2* and contrast agent concentration in blood were applied to t...

a novel computational fluid dynamics and molecular kinetic theory (cfd-mk) method was developed to simulate the impingement of a nanodroplet onto a solid surface. a numerical solution of the navier–stokes equation using a volume-of-fluid (vof) technique was used to model nanodroplet deformation. dynamic contact angle during droplet impact was obtained by molecular kinetic theory. this dynamic c...

In this work incompressible two-phase flows are considered. The aim is to model high density-ratio flows with arbitrary complex interface topologies, such as occur in air/water flows. Between the phases a sharp front exists, where density and viscosity change abruptly. The computational method used in this paper is the mass conserving level-set method. It is based on the level-set methodology, ...

We implement a volume-of-fluid algorithm with a parabolic re-construction of the interface for the calculation of the surface tension force VOF-PROST). This achieves higher accuracy for drop deformation simulations in comparison with existing VOF methods based on a piecewise inear interface re-construction. The algorithm is formulated for the Giesekus constitutive law. The evolution of a drop s...

Volume Of Fluid (VOF) is one of the most powerful methods to resolve free surface ows. In this study, a new algorithm is developed in a curvilinear coordinate system, which implements an implicit pressure based method (SIMPLE) with a staggered grid and a Lagrangian propagation of the interface, using the VOF method in the computational domain. Based on this algorithm, a computer code is generat...

The Moment-of-Fluid(MoF)methodis an extension ofpopular Volume-ofFluid(VoF)techniquefor trackingmaterialinterfaceinmulti-materialfluidflows. VoFmethods trackthe cell-wise material volumes anduse these data for reconstructingtheinterfacesinmixedcell. TheMoFmethodgoes one stepfurther and, in additional to the volumes,keeps trackofthe cell-wise material centroids;this approachprovides sufficiently...

A two-dimensional liquid metal droplet moving into magnetic field gradient regions in a vacuum space in the absence of gravity has been simulated in VOF-CSF method. The general one-fluid VOF model for tracking free surfaces, and associated CSF model for applying surface tension to free surfaces are formulated. The calculations show us that the droplet encounters strong magnetohydrodynamics (MHD...

In this study the developed procedure of Advection in Volume of Fluid (VOF) method for free surface modeling is presented. Two-step projection method is implemented for solution of RANSE equations discretized by finite difference method on the staggered and Cartesian grids. Applying Youngs’ algorithm in staggered grids, assuming that fluid particles in the cell have the same velocity of the cel...

Nano imprint lithography(NIL) is a cost-efficient, highthroughput processing technique to transfer nano-scale patterns onto thin polymer films. Polymers used as the resist include UV cured resins as well as thermoplastics such as polymethyl-methacrylate(PMMA). In this study, an analytic investigation was performed for the NIL process of transferring nano scale patterns onto polymeric films. Pro...