Electrical impedance tomography: from topology to shape

A level set based shape and topology optimization approach to electrical impedance tomography (EIT) problems with piecewise constant conductivities is introduced. The proposed solution algorithm is initialized by using topological sensitivity analysis. Then it relies on the notion of shape derivatives to update the shape of the domains where conductivity takes different values

A Self-Sealing Modular Microfluidic System Using PDMS Blocks With Magnetic Connections

A modular microfluidic system can be used to quickly set up an individually adaptable microfluidic network by linking and delinking different functional building blocks. We present a convenient and reliable connection technology, which is based on magnets and casted O-ring-like structures leading to a sealed connection without the need of additional sealing materials. Based on an improved, previously presented fabrication technology, modular microfluidic polydimethylsiloxane (PDMS) blocks using a polyurethane (PU) mold, 3D printed acrylonitrile butadiene styrene (ABS) channel structures and a magnetic connection system in combination with a casted O-ring link, featuring various integration technologies have now been designed and experimentally evaluated. In particular, this paper will address the realization of directional valves, reciprocating pumps, finger pumps, directly-cast check- and Tesla-valves, fluidic flow sensors, fluidic mixers, commercial valves, and various sensors. By using different measurement setups, the feasibility of these devices is demonstrated. Moreover, limitations and issues encountered during fabrication as well as future work are discussed