On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

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

Study of doubly strange systems using stored antiprotons

Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P‾ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ−-atoms will be feasible and even the production of Ω−-atoms will be within reach. The latter might open the door to the |S|=3 world in strangeness nuclear physics, by the study of the hadronic Ω−-nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions

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

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Vlak verslag 4.4

Deze dataset bestaat uit vier deel verslagen van VLAK-verslag 4. Het betreft 4.1 Basisverslag, 4.2 Botmateriaal, 4.3 Archeobotanie en 4.4 Aardewerk Uit historische bronnen is bekend dat er op d’ Engelsche Boomgaert in de Late Middeleeuwen een boomgaard heeft gelegen. De oudste bebouwing voert terug tot minimaal 1561, toen er reeds een klein huis op het terrein stond, en kort na 1628 verscheen er ook een boerderij, ‘d’ Engelsche Boomgaert’ genaamd. Het archeologische onderzoek heeft zich in eerste instantie gericht op het aansnijden van de oeverwallen uit de Late IJzertijd en Romeinse Tijd waarop bewoningssporen verwacht mogen worden. Daarnaast moest meer inzicht worden verkregen in het terreingebruik tussen de 12e eeuw en 1561, toen d’ Engelsche Boomgaert voor de eerste keer historisch aantoonbaar bebouwd raakte. Het archeozoölogisch onderzoek van d’ Engelsche Boomgaert 6.123 betreft botmateriaal uit twee perioden die qua tijdsspanne te ver uit elkaar liggen om ontwikkelingen in de loop van de tijd te kunnen belichten. De eerste periode betreft restanten van een Late IJzertijd bewoning op een oeverwal. Het materiaal uit deze periode is mogelijk gecontamineerd met enig materiaal uit de Romeinse Tijd. Het materiaal uit de tweede periode is afkomstig uit een laatmiddeleeuwse kasteelgracht. Van beide perioden is apart het economisch gebruik van de dieren worden beschreven. Voor het archeobotanisch onderzoek zijn monsters genomen van de bewoningslaag uit de Late IJzertijd, een inheems-Romeinse damstructuur en uit de kasteelgracht (1275-1351). Het doel van het botanische onderzoek is inzicht te verkrijgen in het landschap en de verbouwde gewassen in de voornoemde perioden. Uit de grachten werden 3485 scherven verzameld uit de gebruiksperiode van het kasteel. Het aardewerk biedt goede mogelijkheden het kasteelterrein te dateren. Het begin is wat moeilijk nauwkeurig te bepalen maar ligt ergens in het midden van de 13e eeuw. Met name het voorkomen van protosteengoed kannen met verdikte naar binnen toe afgeschuinde geprofi leerde randen (type I) duidt op een datering vóór het laatste kwart van de 13e eeuw. De einddatering van het kasteel is rond 1350 te plaatsen. Dit betekent dat het kasteel nog geen 100 jaar heeft gefunctioneerd. Het is verleidelijk de einddatum in verband te brengen met de Hoekse en Kabeljauwse twisten in het midden van de 14e eeuw. Veel kastelen zijn daarbij verwoest en dat kan voor dit kasteel ook het geval zijn. Het gaat echter te ver om alleen op grond van de datering een verband met deze historische gebeurtenissen te leggen

A randomised comparison of bilateral recession versus unilateral recession-resection as surgery for infantile esotropia.

Contains fulltext : 79824.pdf (publisher's version ) (Closed access)OBJECTIVE: Infantile esotropia, a common form of strabismus, is treated either by bilateral recession (BR) or by unilateral recession-resection (RR). Differences in degree of alignment achieved by these two procedures have not previously been examined in a randomised controlled trial. DESIGN: Controlled, randomised multicentre trial. SETTING: 12 university clinics. PARTICIPANTS AND INTERVENTION: 124 patients were randomly assigned to either BR or RR. Standardised protocol prescribed that the total relocation of the muscles, in millimetres, was calculated by dividing the preoperative latent angle of strabismus at distance, in degrees, by 1.6. MAIN OUTCOME MEASURE: Alignment assessed as the variation of the postoperative angle of strabismus during alternating cover. RESULTS: The mean preoperative latent angle of strabismus at distance fixation was +17.2 degrees (SD 4.4) for BR and +17.5 degrees (4.0) for RR. The mean postoperative angle of strabismus at distance was +2.3 degrees (5.1) for BR and +2.9 degrees (3.5) for RR (p = 0.46 for reduction in the angle and p = 0.22 for the within-group variation). The mean reduction in the angle of strabismus was 1.41 degrees (0.45) per millimetre of muscle relocation for RR and 1.47 (0.50) for BR (p = 0.50 for reduction in the angle). Alignment was associated with postoperative binocular vision (p = 0.001) in both groups. CONCLUSIONS: No statistically significant difference was found between BR and RR as surgery for infantile esotropia