65 research outputs found

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

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    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)

    Overview of the JET results in support to ITER

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    Antimicrobial effect of a dental varnish, in vitro

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    The effects of a polymer based antimicrobial releasing varnish Cervitec(R) were investigated against different grampositive and gramnegative bacterial strains as well as a yeast using the agar diffusion inhibitory test (ADT-test in vitro). As positive controls a 1 % chlorhexidine gel and 1 % aqueous solution of thymol and a placebo polymer varnish without active agents were employed. The test experimental varnish containing 1 % chlorhexidine and 1 % thymol showed antimicrobial activity against all grampositive and gramnegative microorganisms tested including one Candida strain. The positive controls were similar in effect compared to the test varnish. No antimicrobial effect was observed with the placebo varnish without active ingredients. Toothpicks and dental floss treated with the test varnish showed an antimicrobial effect against S. mutans even after storing in room temperature up to 12 months. The results from this study support earlier laboratory studies that chlorhexidine and thymol diffuse out of the experimental varnish and that the varnish is active against various of oral pathogenes. The possibility to use toothpicks or dental floss impregnated with the varnish with the aim to become chemotherapeutically active against periodontal diseases as well as against dental caries, is promising and should be tested in vivo
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