194 research outputs found

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

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    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

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    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

    Clarifying the dilemmas about inhalation techniques for dry powder inhalers: integrating science with clinical practice

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    This review integrates pharmaceutical science with routine clinical practice to explain why inhalation manoeuvres through a dry powder inhaler (DPI) should start with a gentle exhalation, away from the inhaler. Place the inhaler in the mouth and ensure the lips form a tight seal. This should be followed by an immediate forceful inhalation that is as fast as possible and continued for as long as the patient can comfortably achieve. Although this is universally accepted, there has been a lot of attention on inhalation flow as an indicator of adequate inspiratory effort. This has led to the wrong assumption that inhalation flows through each DPI should be the same, and that low flows through some DPIs suggest that dose delivery is impaired. Most miss the concept that inhalation flow together with the resistance of the DPI combine to create a turbulent energy which de-aggregates the formulation and provides an effective emitted dose. A low flow through a DPI with high resistance generates the same turbulent energy as fast flow with low resistance. Therefore, depending on the device, different inhalation flows are compatible with potentially effective use. Flow measurements should be a guide to train patients to inhale faster. The focus of inhaler technique training should be the use of the above generic inhalation manoeuvre
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