Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Research data supporting the publication "Acoustic levitation of pollen and visualisation of hygroscopic behaviour"

Data, metadata and code accompanying the paper 'Acoustic levitation of pollen and visualisation of hygroscopic behaviour' (Mills, S.A., Milsom, A., Pfrang, C., MacKenzie, A.R., Pope, F.D., 2023). Correspondence to: Francis D. Pope ([email protected]

SAFIRA. Teilprojekt B 3.1: Reduktive Dechlorierung von Chloraromaten mit elektrochemischen Methoden und Membran-gestuetzten Katalysatoren zur in-situ-Behandlung von kontaminierten Grundwaessern Abschlussbericht

The objective of the sub-project was the development and experimental testing of a mainly passive, in situ technology for the abiotic dehalogenation of halogenated organic hydrocarbons (HOCs) within the aquifer. The technology to be developed should be applicable not only for aliphatic HOCs but also for dehalogenation of aromatic halogenated pollutants. During the first two years of the project, the main focus of our research was the development and testing of novel membrane-supported catalysts. The catalytically active component Pd was embedded in highly disperse form into non-porous silicone membranes in order to protect it from ionic catalyst poisons and erosion. At the laboratory scale, the novel catalysts proved their suitability for dehalogenation of various classes of HOCs within the water phase. The membrane-supported catalysts were developed in co-operation with a working group from the GKSS Geesthacht and their novelty was protected in a patent disclosure (DE 19952 732A1). Especially for their use under field conditions, membrane-supported Pd catalysts were produced as hollow fibres where the reaction partner hydrogen was fed from the interior of the fibres. Unfortunately, the high activity of these catalysts was not sustainable under Bitterfeld groundwater conditions - sulphur poisoning occurred due to non-ionic catalyst poisons situated in the aquifer and H_2S produced by sulphate-reducing bacteria. In order to enhance the catalyst stability and therefore their applicability in a scaled-up technology, our studies were then focused on the suppression of microbial activity and on catalyst regeneration. (orig.)Das Ziel des Teilprojektes war die Entwicklung und experimentelle Pruefung eines weitgehend passiven, in-situ-tauglichen Verfahrens zur abiotischen Dehalogenierung von HKW im Aquifer, das auch auf halogenierte aromatische Verbindungen anwendbar ist. In den ersten zwei Jahren des Projektes stand die Entwicklung und Testung von Membran-gestuetzten Palladiumkatalysatoren im Mittelpunkt unserer Untersuchungen, bei denen das Pd in hochdisperser Form in unporoese Silikonmembranen eingebettet ist, um es gegen Vergiftung durch ionische Verbindungen und Erosion zu schuetzen. Im Labormassstab konnte die prinzipielle Eignung Membran-gestuetzter Pd-Katalysatoren zur Dechlorierung von HKW in waessriger Phase nachgewiesen werden. Die Entwicklung des Membrankatalysators erfolgte in Zusammenarbeit mit einer Forschungsgruppe der GKSS. Zum Einsatz der neuartigen und zum Patent angemeldeten Katalysatoren (Offenlegungsschrift DE19952 732A1) unter Feldbedingungen wurden von uns Membrankatalysatoren entwickelt, welche als aktive Katalysatorkomponente palladisierte Hohlfasern enthielten. Die Aktivitaet unserer Katalysatoren wurde unter Feldbedingungen durch im Grundwasser enthaltene sulfidische Schwefelverbindungen beeintraechtigt. Um die Standfestigkeit der Katalysatoren und damit die Aussicht auf eine grosstechnische Verwertung unserer Erfindung zu erhoehen, galt unser Interesse neben der Unterdrueckung der mikrobiellen Sulfidbildung der Regenerierung der Katalysatoren. (orig.)Available from TIB Hannover: F03B236+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman

Optimal eradication: when to stop looking for an invasive plant

The notion of being sure that you have completely eradicated an invasive species is fanciful because of imperfect detection and persistent seed banks. Eradication is commonly declared either on an ad hoc basis, on notions of seed bank longevity, or on setting arbitrary thresholds of 1% or 5% confidence that the species is not present. Rather than declaring eradication at some arbitrary level of confidence, we take an economic approach in which we stop looking when the expected costs outweigh the expected benefits. We develop theory that determines the number of years of absent surveys required to minimize the net expected cost. Given detection of a species is imperfect, the optimal stopping time is a trade-off between the cost of continued surveying and the cost of escape and damage if eradication is declared too soon. A simple rule of thumb compares well to the exact optimal solution using stochastic dynamic programming. Application of the approach to the eradication programme of Helenium amarum reveals that the actual stopping time was a precautionary one given the ranges for each parameter

The provocation of the humanitarian social imaginary

This article reviews recent attempts to analyse the visibility that is brought to human suffering within 'social imaginaries' committed to humanitarian concerns. It questions the conventions of critique that operate to cast the humanitarian social imaginary as a negative development within our political culture. It is designed to encourage a more critically reflexive and historically informed approach to the work of critique. It also argues that it is possible to trace a tradition in which humanitarian campaigners operate with the aim of appropriating the critical reaction to their work as part of their political strategy. In this regard, campaigners are more concerned to provoke moral controversy than to fashion 'winning arguments'. Here the visualization of human suffering is valued more for its potential to generate value conflicts than for the extent to which it serves as an authentic or ideologically uncontaminated representation of social reality