Eberhard Schluecker

Injection of ethanol into supercritical CO 2 : Determination of mole fraction and phase state using linear Raman scattering

For the pulsed injection of liquid ethanol into supercritical CO(2) inside an optically accessible chamber, for the first time to the best of our knowledge the spatially and temporally resolving linear Raman scattering technique was used to simultaneously determine the mole fraction and the corresponding phase state in the ethanol jet. The mole fraction was identified by calculating the ratio of the C-H band Raman signal (2950 cm(-1)) of ethanol and the CO(2) Raman signal. The magnitude of this ratio was found to be phase state sensitive. Thus, the phase state of the mixture of ethanol and CO(2) could be classified as being homogeneous liquid, homogeneous supercritical or not yet homogeneously mixed.

Underwater interferometric radar sensor for distance and vibration measurement

With the growing application of autonomous underwater vehicles (AUV) and underwater construction, i.e. robotic manipulator and maintenance systems, there is an increasing demand on precise underwater distance sensors. In this paper we present a low-cost, short-range and contactless sensor which uses electromagnetical (EM) waves for measuring distances underwater. The measurement system is based on interferometric radar applying a six-port interferometer and using EM waves at a frequency of 2.4 GHz. Measurement series in fresh water have been carried out showing an precision of below 100 μm up to a distance of 35 mm with only 8 dBm of transmit power. Due to the high measurement rate the system can also be employed for vibration analysis. Additionally, by connecting a commercial 2.4 GHz data transceiver, it is imaginable for the system to be simultaneously used for high data rate communication between, e.g. AUV and unmanned underwater platforms (UUP).