Publications by authors named "Andre Bieberle"

Engineers, geomorphologists, and ecologists acknowledge the need for temporally and spatially resolved measurements of sediment clogging (also known as colmation) in permeable gravel-bed rivers due to its adverse impacts on water and habitat quality. In this paper, we present a novel method for non-destructive, real-time measurements of pore-scale sediment deposition and monitoring of clogging by using wire-mesh sensors (WMSs) embedded in spheres, forming a smart gravel bed (GravelSens). The measuring principle is based on one-by-one voltage excitation of transmitter electrodes, followed by simultaneous measurements of the resulting current by receiver electrodes at each crossing measuring pores.

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Ultrafast X-ray computed tomography is an advanced imaging technique for multiphase flows. It has been used with great success for studying gas-liquid as well as gas-solid flows. Here, we apply this technique to analyze density-driven particle segregation in a rotating drum as an exemplary use case for analyzing industrial particle mixing systems.

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We present a modular and cost-effective gamma ray computed tomography system for multiphase flow investigations in industrial apparatuses. It mainly comprises a Cs isotopic source and an in-house-assembled detector arc, with a total of 16 scintillation detectors, offering a quantum efficiency of approximately 75% and an active area of 10 × 10 mm each. The detectors are operated in pulse mode to exclude scattered gamma photons from counting by using a dual-energy discrimination stage.

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In this paper, a smart detector design for novel multi-plane ultrafast electron beam X-ray computed tomography is presented. The concept is based on multi-plane electron beam scanning on a transparent X-ray target and elongated cuboid-shape scintillation detectors for radiation detection over an extended axial scanning range. The optical part of the scintillation detector acts as both an X-ray sensitive scintillator with a fast time response and a light guide.

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Computed tomography (CT) is known for giving cross-sectional images of a body. As tomographic scans require mechanical movement of components, data acquisition is commonly too slow to capture dynamic processes, which are faster than the acquisition time for a single image. Time-averaged angle-resolved CT imaging is a more recent method, which has demonstrated a capability to sharply image fast rotating machinery components by synchronizing data acquisition with rotation.

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In this paper, a thermal control design for a high-resolution gamma-ray computed tomography detector is presented. It accounts for the generation of heat produced by active electronic components as well as heat transfer from external heat sources. The development and implementation of this feature were motivated by stringent requirements for measurement accuracy at thermal hydraulic test facilities, where ambient thermal conditions are constantly changing.

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