The present research work investigated the acoustic manipulation of bioparticles and cells in closed and liquid-filled vessels using a special method for focusing acoustic fields. Based on simulation studies, the feasibility of particle manipulation with this method was successfully demonstrated. Successful final testing using a demonstrator and thus the transfer and prospective application in biotechnology are part of further research work.

A miniaturized, field-applicable sensor system was developed for the measurement of low hydrogen (H₂) concentrations in air. The sensor system is based on the application of a newly developed miniaturized coulometric detector with gas chromatographic (GC) pre-separation after injection. By optimizing all operational parameters, it was possible to conduct reproducible and 100 % selective H₂ measurements with more than 90 % analyte turnover compared to Faraday's law.

Air-coupled ultrasound is a non-contact non-destructive testing method. In many cases air-coupled ultrasound is used in a transmission mode requiring access from both sides of the specimen. Air-coupled ultrasound can be used in a re-emission mode enabling single-sided testing. In this work a sensor head with automatically adjustable ultrasound probes was developed to make one-sided air-coupled ultrasound easier. With this integrated sensor head it is possible to detect defects in thin walls.

A new approach with an acousto-thermal nondestructive testing technique was developed and integrated into a mobile prototype NDT device. It is based on well-known ultrasonic thermography and uses hardware, specimen and local defect resonances for efficient excitation. It was specifically designed for fast and easy-to-interpret application in impact damage detection. Its handheld design allows for mobile usage at impact-injured FRP structures with a testing time of only 1 min.

We describe a mechanical model based on the beam theory for the development of a beam-like sensor switch with switching hysteresis for humidity sensing. The hydrogel swelling provides the mechanical energy to deflect the partly hydrogel-covered bending beam via the bimorph effect. From the model, we calculate the deflection of a beam-like sensor switch with and without a switching hysteresis. A beam-like sensor switch was manufactured, and the switching hysteresis was successfully demonstrated.