Membrane-free microfiltration by asymmetric inertial migration is studied and evidence of the filtration capability is presented. Centrifugal force induced by flow in spiral channel geometry modifies the lateral symmetry of straight-channel tubular pinch equilibrium resulting in a focused particle band nearer to the inner sidewall. Bifurcated outlets separately collect the concentrated particle band and remaining effluent. The spiral continuous flow filtration relies solely on internal fluidic shear characteristics, eliminating the need for membrane filters or external force fields. This device has the desirable combinations of high throughput and low cost, making it inherently suited for preparative filtration in the range of micro- to macroscale applications.

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For energy storage applications, it is critical that the dielectric material possesses low losses, especially the conduction losses, which could become significant at high temperatures and high electric fields. We investigate the conduction at fields up to 100 MV/m and high temperatures in a semi-crystalline poly(tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) terpolymer which has been shown to be attractive for high energy density capacitors. Experimental results show that the insulating nanofillers are very effective in reducing the conduction current, i.e., a more than two orders of magnitude reduction in conduction can be achieved with less than 1 wt. % (<0.5 vol. %) of Al2O3 nanofillers. Experimental measurements are compared with multiscale simulations, which shows that the dominant conduction mechanism, i.e., carrier hopping in the polymer, is markedly reduced owing to a large decrease in the mobile carrier concentrations and increased trap depth, caused by the nanofillers.

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Use of the Green function, for the solution of boundary-value problems, frequently results in singular integral equations. Algorithms arc presented for the accurate and efficient treatment of singular kernels frequently encountered in the boundary element method (BEM). They are based upon the use of appropriately weighted Gaussian quadrature formulae, together with numerical geometrical transformations of the region of integration. The use of high-order subdomain expansion functions, for interpolation over nonplanar elements, allows boundary curvature to be accommodated. In particular, thc handling of Green functions with logarithmic and r -' behaviour are detailed. Volume integrals, with r singularity, are outlined.Operations are performed on a simplex, thus resulting in generality and ease of automation. This scheme has been incorporated into boundary element method software and successfully applied to a variety of problems.