in this paper, the direct extrusion process of bimetallic rods in conical dies is analyzed by an improved upper bound method. the deformation zone is subdivided into six smaller zones and by considering a non-spherical entrance boundary to the deformation zone, a velocity field is presented which is different from velocity fields employed in previous studies. the total power consumption of the ...

The velocity tracking problem for the evolutionary Navier-Stokes equations in 3d is studied. The controls are of distributed type and they are submitted to bound constraints. The classical cost functional is modified so that a full analysis of the control problem is possible. First and second order necessary and sufficient optimality conditions are proved. A fully-discrete scheme based on disco...

the main purpose of this study is to introduce a new method for nanofibers by bulk layer production. in the present method the effect of some parameters including take-up velocity, applied voltage, polymer solution concentration on density of produced layers is investigated. the compression characteristic of nanofiber layers produced under optimum electrospinning is also investigated. it was sh...

With enhancing mixing in micro- or nanofluidic applications in mind, the problem of maximizing fluid transport across a fluid interface subject to an available energy budget is examined. The optimum cross-interface perturbing velocity is obtained explicitly in the time-periodic instance using an Euler-Lagrange constrained optimization approach. Numerical investigations which calculate transferr...

The problem of designing an atom interferometer with optimum sensitivity to de Broglie wave phase shifts is revisited. Because van der Waals interactions affect how efficiently material gratings work as beam splitters, we find the optimum open fraction for each of the gratings in a three-grating Mach Zehnder atom interferometer depends on the van der Waals interaction strength as well as the at...

BACKGROUND AND PURPOSE Many reports in the medical literature have proposed methods of differentiating between gaseous and particulate emboli detected with the use of transcranial Doppler ultrasound. The purpose of this study was to compare the previously published methods with our own sample volume length (SVL) parameter to assess the accuracy of each method in classifying emboli. METHODS A ...

An analytical method is developed for the reconstruction of velocity profiles using measured potential distributions obtained around the boundary of a multi-electrode electromagnetic flow meter (EMFM). The method is based on the Discrete Fourier Transform (DFT), and is implemented in Matlab. The method assumes the velocity profile in a section of a pipe as a superposition of polynomials up to 6...