Real-time model predictive control of a wastewater treatment plant based on machine learning.

Two separate goals should be jointly pursued in wastewater treatment: nutrient removal and energy conservation. An efficient controller performance should cope with process uncertainties, seasonal variations and process nonlinearities. This paper describes the design and testing of a model predictive controller (MPC) based on neuro-fuzzy techniques that is capable of estimating the main process variables and providing the right amount of aeration to achieve an efficient and economical operation. This algorithm has been field tested on a large-scale municipal wastewater treatment plant of about 500,000 PE, with encouraging results in terms of better effluent quality and energy savings.

High resolution gamma-ray spectrometer with MHz capabilities for runaway electron studies at ASDEX Upgrade.

A new gamma-ray spectrometer with MHz capabilities has been developed to measure the bremsstrahlung emission spectrum in the gamma-ray energy band generated by MeV range runaway electrons in disruption experiments at ASDEX Upgrade. Properties of the runaway electrons are inferred from the measured bremsstrahlung spectrum by a deconvolution technique, particularly with regard to their maximum energy. Changes induced to the runaway electron velocity space are unambiguously observed both in massive gas injection and resonant magnetic perturbation experiments with the detector.

Velocity-space sensitivities of neutron emission spectrometers at the tokamaks JET and ASDEX Upgrade in deuterium plasmas.

Future fusion reactors are foreseen to be heated by the energetic alpha particles produced in fusion reactions. For this to happen, it is important that the energetic ions are sufficiently confined. In present day fusion experiments, energetic ions are primarily produced using external heating systems such as neutral beam injection and ion cyclotron resonance heating. In order to diagnose these fast ions, several different fast-ion diagnostics have been developed and implemented in the various experiments around the world. The velocity-space sensitivities of fast-ion diagnostics are given by so-called weight functions. Here instrument-specific weight functions are derived for neutron emission spectrometry detectors at the tokamaks JET and ASDEX Upgrade for the 2.45 MeV neutrons produced in deuterium-deuterium reactions in deuterium plasmas. Using these, it is possible to directly determine which part of velocity space each detector observes.

Characterisation of a BC501A compact neutron spectrometer for fusion research.

The compact neutron spectrometer used at the ASDEX Upgrade tokamak is characterised to obtain its response matrix. This paper describes the characterisation procedure and the derived response matrix, based on a campaign at the PTB ion accelerator facility (PIAF) and on the subsequent time-of-flight (TOF) analysis of neutrons from a field with a broad energy distribution. The response of mono-energetic neutrons generated at the PIAF is used as reference for the TOF analysis. The detector's response functions for spectrum deconvolution are obtained by Gaussian broadening of the simulated responses to fit the experimental ones, using a maximum-entropy ansatz. In this way, the response functions are smooth enough to ensure a reliable unfolding of pulse height spectra into neutron emission spectra, which provide information on the fast ion velocity distribution in neutral beam heated tokamak plasmas.

Optic neuritis associated with influenza B virus meningoencephalitis.

Various postinfectious neurological manifestations have been described associated to influenza viruses. Optic neuritis is a serious, often reversible disease reported among several infectious diseases and vaccines complications. We report a case of optic neuritis following an influenza B virus infection in a 10-year-old male.

The compact neutron spectrometer at ASDEX Upgrade.

The first neutron spectrometer of ASDEX Upgrade (AUG) was installed in November 2008. It is a compact neutron spectrometer (CNS) based on a BC501A liquid scintillating detector, which can simultaneously measure 2.45-MeV and 14-MeV neutrons emitted from deuterium (D) plasmas and γ radiation. The scintillating detector is coupled to a digital pulse shape discrimination data acquisition (DPSD) system capable of count rates up to 10(6) s(-1). The DPSD system can operate in acquisition and processing mode. With the latter n-γ discrimination is performed off-line based on the two-gate method. The paper describes the tests of the CNS and its installation at AUG. The neutron emission from the D plasma measured during a discharge with high auxiliary heating power was used to validate the CNS performance. The study of the optimal settings for the DPSD data processing to maximize the n-γ discrimination capability of the CNS is reported. The CNS measured both 2.45-MeV and 14-MeV neutrons emitted in AUG D plasmas with a maximum count rate of 5.4 × 10(5) s(-1) (>10 times higher than similar spectrometers previously achieved) with an efficiency of 9.3 × 10(-10) events per AUG neutron.

Evidence of inward toroidal momentum convection in the JET tokamak.

Experiments have been carried out on the Joint European Torus tokamak to determine the diffusive and convective momentum transport. Torque, injected by neutral beams, was modulated to create a periodic perturbation in the toroidal rotation velocity. Novel transport analysis shows the magnitude and profile shape of the momentum diffusivity are similar to those of the ion heat diffusivity. A significant inward momentum pinch, up to 20 m/s, has been found. Both results are consistent with gyrokinetic simulations. This evidence is complemented in plasmas with internal transport barriers.

Density peaking, anomalous pinch, and collisionality in tokamak plasmas.

The existence of an anomalous particle pinch in magnetized tokamak plasmas is still questioned. Contradictory observations have been collected so far in tokamaks. Clear experimental evidence that density peaking in tokamak plasmas drops with increasing collisionality is provided for the first time. This phenomenon is explained by means of existing theoretical models based on the fluid description of drift wave instabilities, provided that such models include the dissipative effects introduced by collisions on the mentioned instabilities. These results reconcile the apparent contradictions found so far in the experiments.