The principles of bioanalytical systems for an on-line bioprocess monitoring are described within this paper. These sensor systems can be interfaced to the bioprocess in different ways according to the needs of the single bioprocess. Modular systems are necessary, which can fit exactly to the needs of the single process. Invasive as well as non-invasive bioanalytical tools are described and discussed in detail. Immunosensors give the possibility to monitor high molecular weight components within short time intervals. Non-invasive optical sensors allow the direct monitoring of various analytes such as oxygen pH for the complex fluorescence behavior of the bioprocess medium. These so-called fluorescence sensors offer the possibility to monitor intra-as well as extracellular components without interfering with the bioprocess. An industrial example for the application of bioanalytical tools for a process optimization are presented in this application. Here a biosensor system is used to optimize the downstreaming of molasses on a technical scale. The economic as well ecological advantages are discussed.

The MATHLAB routine is free available on request from the authors.

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Communication: In this paper, the author demonstrates with examples how simple titrimetric techniques can be applied to efficient process control. Important process parameters, such as cell densities and product concentrations, are computed or estimated on the basis of titrimetric data. Great importance was attached to keeping applications as simple as possible. So, it is not required that biomass be separated prior to analysis. With that a source of disturbance can be minimized. Efficient Monitoring of Biotechnological Processes by Means of Titration

Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counterintuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfvén waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, α = 2 as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed >600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: preflare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that α = 1.63 ± 0.03. This is below the critical threshold, suggesting that Alfvén waves are an important driver of coronal heating.