the role of polymeric additives such as pvp and peg is studied with respect to the morphology of pes porous layer as a sublayer of nanofiltration composite membranes based on pes/pa. results show that by phase inversionprocess of quaternary systems comprised of four components of polymer/solvent/non-solvent/additive and the diffusion of intertwined polymers some changes occur in membrane morpho...

The entropy generation rate in a laminar flow through a channel filled with saturated porous media is investigated. The upper surface of the channel is adiabatic and the lower wall is assumed to have a constant heat flux. The Brinkman model is employed. Velocity and temperature profiles are obtained for large Darcy number (Da) and used to obtain the entropy generation number and the irreversibi...

The pressure drop in microchannels filled with porous media formed by square arrays of cylinders (micro-porous channels) is investigated. Combining the Brinkman equation and the existing models for permeability of regular arrays of cylinders, the pressure drop in the considered micro-porous channels is calculated theoretically. Soft lithography method is used to fabricate several Polydimethylsi...

We demonstrate rapid fabrication of complex three-dimensional (3D) microfluidic channels with lengths up to ~6.0 cm within a tiny volume down to ~80 nl in glass substrates by femtosecond laser direct writing, which, to the best of our knowledge, is the longest microfluidic channel directly embedded in glass by femtosecond laser microprocessing. The fabrication mainly includes the following two ...

Biomimetic scaffolds that replicate the native architecture and mechanical properties of target tissues have been recently shown to be a very promising strategy to guide cellular growth and facilitate tissue regeneration. In this study, porous, soft, and elastic crosslinked urethane-doped polyester (CUPE) tissue engineered nerve guides were fabricated with multiple longitudinally oriented chann...

We introduce a microfluidic device for chemical manipulation and mechanical investigation of circulating cells. The device consists of two crossing microfluidic channels separated by a porous membrane. A chemical compound is flown through the upper "stimulus channel", which diffuses through the membrane into the lower "cell analysis channel", in which cells are mechanically deformed in two sequ...

Breakup of droplets at bi-layer bifurcating junction in polydimethylsiloxane (PDMS) microchannel has been investigated by experiments and numerical simulation. The pressure drop in bi-layer bifurcating channel was investigated and compared with single-layer bifurcating channel. Daughter droplet size variation generated in bi-layer bifurcating microchannel was analyzed. The correlation was propo...

Various chromatography systems are today widely applied for both analysis and preparation of chemical compounds from complex mixtures. Current trends aim at the miniaturization of such systems, for instance on microchips. One approach is to arrange arrays of small pillars in a micro channel. The pillar surfaces are functionalized such as to adsorb specific substances from a bulk fluid which flo...

An analytical characterization of forced convective ~ow through a channel _lled with a porous medium is presented in this work[ Based on a two!equation model\ including transverse conduction contributions\ exact solutions are obtained for both ~uid and solid phase temperature _elds[ The Nusselt number is also obtained in terms of the pertinent physical parameters\ namely the Biot number for the...