Journal articles and book contributions

This paper presents an improved experimental setup for the contactless flow rate measurement in a weakly electrically conducting fluid on the base of Lorentz force velocimetry (LFV) and discusses the measurement results. The new setup embodies major improvements over the setup reported inWegfraß et al. (Appl Phys Lett 100:194103, 2012). This measurement setup consists of a newly designed fluid channel with well defined flow profiles - a plug profile at the inlet and quasi parabolic profile at the outlet of the test section. Another improvement is the force measurement system which is based on electromagnetic force compensation (EMC). Furthermore an optimized Halbach array is used as a magnet system. The results of our measurements confirm the feasibility of LFV in a model fluid (salt water) with conductivities less than 10 Sm-1 and demonstrate that the optimized magnet system increases the measurement signal. The used force measurement system had to be particularly calibrated for this purpose, so that in combination with the new magnet system design a three times higher signal resolution for the fluid velocity under laboratory conditions was achieved.

In this work a non-contact biaxial nanoprobe for surface profile scans of macroscopic objects with 150 nm accuracy is presented. The biaxial nanoprobe oscillates in two directions to overcome the challenges of sticking in contact mode. Two electrostatic actuators drive the nanoprobe while two electrostatic sensors measure the position of the tip ball. The contact behavior between the tip ball and the specimen is determined by the contact stiffness and the contact damping. Dependent on the dominating effect the nanoprobeoperatesat semi- or non-contact mode, respectively. The aims of this paper are the investigation of the contact behavior, the proof of the independent evaluation of the two axes and the check if sticking is safely avoided.