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An image-reconstruction approach for optical tomography is presented, in which a layered back-propagation neural network is used to reconstructs two-dimensional images of two-phase gas-liquid flow using wire-mesh sensor data as target by means of Levenberg-Marquardt algorithm. The network learns the relationship between the reference sensor measurements and optical tomography projections. Results...
For the investigation of multiphase flows, i.e. in oil production, there are only few suitable measuring techniques. For this reason, in this paper a new multichannel complex impedance measuring system using wire-mesh sensors is presented. The novel system measures amplitude and phase components of impedance (at single frequency) and is thus able to evaluate simultaneously the conductive and the capacitive...
An ultra fast electron beam CT scanner is introduced which has been developed for flow measurement applications. Its basic design comprises an electron gun with beam optics and fast electromagnetic deflection system and an ultra fast X-ray detector based on room-temperature semiconductor converters. As in other tomographic imaging modalities radiographic projections are generated by a moving X-ray...
Electron beam CT has until today been exclusively used in cardiac imaging of human beings. As a high cost diagnostic tool with frame rates in the range of 20 s−1 it has so far not been considered for small animal imaging. With recent progress in technology an application in this field becomes feasible. Especially perfusion imaging for heart and other organs using iodine based contrast agents may be...
Ultra fast electron beam tomography has been developed as a novel tool for visualization of fast processes. As in medical electron beam computed tomography (CT) this technique is based on the generation of images from radiographs produced with a rapidly scanned electron beam. Scanning frequencies of few thousand frames per second require X-ray detectors which can be read out at rates up to one megahertz...
We present results of a GATE simulation study on the role of different design parameters for the count rate accuracy of a high resolution gamma ray detector used for transmission tomography. The considered gamma ray tomography system is operated with a 137Cs isotopic source and a special detector comprising 320 single elements, made of lutetium yttrium orthosilicate (LYSO) scintillators coupled to...
For the investigation of three- or multiphase flows, which are of interest for instance in the chemical engineering or in oil extraction and processing, there are only few suitable measuring techniques. For this reason we have developed a high-speed complex admittance/permittivity needle probe. Such probes are able to distinguish the different phases or components of a flow by measuring the complex...
We introduce a novel combined temperature and conductivity needle probe measuring system for local void fraction measurements in two-phase flow experiments. The system is able to deal with direct sheathed micro thermocouples as well as open thermocouples. It consists of a thermo needle probe connected to a special electronic circuit using AC measuring technique for the conductivity measurements and...
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