Investigation of a Bubble Detector based on Active Electrolocation of Weakly Electric Fish

Weakly electric fish employ active electrolocation for navigation and object detection. They emit an electric signal with their electric organ in the tail and sense the electric field with electroreceptors that are distributed over their skin. We adopted this principle to design a bubble detector that can detect gas bubbles in a fluid or, in principle, objects with different electric conductivity than the surrounding fluid. The evaluation of the influence of electrode diameter on detecting a given bubble size showed that the signal increases with electrode diameter. Therefore it appears that this detector will be more appropriate for large sized applications such as bubble columns than small sized applications such as bubble detectors in dialysis

Mobile HTS SQUID System for Eddy Current Testing of Aircraft

In Non-Destructive Evaluation (NDE), eddy current techniques are commonly used for the detection of hidden material defects in metallic structures. Conventionally, one works with an excitation coil generating a field at a distinct frequency. The eddy currents are deviated by materials flaws and the resulting distorted field is sensed by a secondary coil. Because of the law of induction, this technique has its limitations in the low frequency range. This leads to a decrease of the Probability of flaw Detection (POD) in larger depths

Modelling a Historic Oil-Tank Fire Allows an Estimation of the Sensitivity of the Infrared Receptors in Pyrophilous Melanophila Beetles

Pyrophilous jewel beetles of the genus Melanophila approach forest fires and there is considerable evidence that these beetles can detect fires from great distances of more than 60 km. Because Melanophila beetles are equipped with infrared receptors and are also attracted by hot surfaces it can be concluded that these infrared receptors are used for fire detection

Das heißisostatische Pressen (HIP) : Technik, Anwendungsmöglichkeiten und Wirtschaftlichkeit

This report gives a survey of the hot isostatic pressing. The single components of the facility and the process technique are explained. Then a summary of the fields of application with examples follows. The reached improvements of the material qualities are demonstrated. Finally the economy of the method is treated

High frequency coupling coefficient between the coplanar resonator and radio frequency SQUID

The coupling coefficient (k(2)) between the superconducting coplanar resonator and the flip chip coupled washer radio frequency SQUID was calculated using computer simulation. The coplanar resonator is formed by two coplanar lines surrounding a flux: concentrator,vith each line having a slit. For a 3 mm x 3 mm washer SQUID with a 100 mu m x 100 pm loop coupled to a coplanar resonator with the slits on opposite sides, we estimated k(2)=7.1x10(-3). However, if the same SQUID is coupled to a coplanar resonator with parallel slits and with a short circuit at the 90 degrees position with respect to the opening slit, k(2) of only 0.5x10(-3) is obtained, which indicates that the k(2) is strongly dependent on the resonator layout. The simulation also shows that k(2) is dependent on the SQUID washer size and the separation distance between the washer SQUID and the coplanar resonator