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The accurate identification of the transition velocities Utrans in bubble columns (BCs) is very important for their effective design, operation and scale-up. In this work, a novel parameter (new hybrid index (NHI)) has been developed and successfully applied to gas holdup and pressure fluctuations recorded in various BCs operated with water and aqueous solutions of alcohols (ethanol and iso-propanol). The first Utrans has been identified on the basis of a well-pronounced local NHI minimum, whereas the second Utrans has been distinguished by the point, from which the NHI profile levels off. It has been concluded that the main Utrans depend on the type of gas-liquid system and sparger used. A set of several Utrans has been reported.

Reactive bubbly flows are found in many chemical and biochemical process-es. They are characterized by complex hydrodynamics that govern global mass transfer and reaction rates. Effects, which have to be taken into account when modelling and simulating the reaction progress are enhanced bubble-bubble interaction and bubble-induced turbulence as well as swarm-induced macro-convection. This poses great challenges on both, experimental analysis and numerical simulation. Bubble swarms at higher gas fractions are opaque, which limits the use of optical flow measurement techniques. Moreover, simu-lations at industrial scale are only feasible with point-bubble-based Euler-Euler or Euler-Lagrange approaches. Such approaches require closure relations, which account for all relevant interfacial forces as well as bubble-induced tur-bulence and coalescence including swarm effects. This chapter describes the progress in the experimental analysis and CFD simulation of reactive bubbly flows achieved during the time of the DFG Priority Programme SPP 1740. Ex-perimental studies in bubble columns reported in this Chapter were carried out at TU Dresden and OVGU Magdeburg. CFD model development and simula-tion has been carried out at OVGU Magdeburg using the Euler-Euler and Euler-Lagrange method and at TU Kaiserslautern and Helmholtz-Zentrum Dresden-Rossendorf using the Euler-Euler approach. As reaction systems the chemi-sorption of CO2 in NaOH solution and the reaction of FeII(edta) with NO were studied.

In this opinion paper, we, a group of scientists from environmental-, geo-, ocean- and information science, argue visual data exploration should become a common analytics approach in Earth system science due to its potential for analysis and interpretation of large and complex spatio-temporal data. We discuss the challenges that appear such as synthesis of heterogeneous data from various sources, reducing the amount of information and facilitating multidisciplinary, collaborative research. We argue that to fully exploit the potential of visual data exploration, several bottlenecks and challenges have to be addressed: providing an efficient data management and an integrated modular workflow, developing and applying suitable visual exploration concepts and methods with the help of effective and tailored tools as well as generating and raising the awareness of visual data exploration and education. We are convinced visual data exploration is worth the effort since it significantly facilitates insight into environmental data and derivation of knowledge from it.

Purpose: The diagnostic role of positron emission tomography (PET) with 2-deoxy-2-[18F]fluoro-D-glucose (FDG) in squamous cell carcinoma of the oral cavity is evaluated. Procedures: In 38 patients, the results of FDG-PET, magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound were compared. The standard uptake values (SUV) of FDG-PET were correlated to histopathological grading and DNA-image cytometry. Results: In the case of lymph node metastases, the sensitivity of FDG-PET (93%) was higher than the sensitivity for the compared methods. The specificity was best for CT. SUVs of diploid tumor cell lines seemed to be lower than in non-diploid tumor cell lines. Conclusions: The high sensitivity and the high negative predictive value of PET may lead to more restrictive therapeutic regimens regarding lymph. node metastases. Studies are necessary regarding possible relationships between glucose metabolism and tumor grading.