Filters

2010 - 20152

More filters

2020 - 20222
Reset filters

Settings

Subject: Atmospheric temperature × WGL Institute: INP ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet
    (College Park, MD : Institute of Physics Publishing, 2010) Koban, I.; Matthes, R.; Hübner, N.-O.; Welk, A.; Meisel, P.; Holtfreter, B.; Sietmann, R.; Kindel, E.; Weltmann, K.-D.; Kramer, A.; Kocher, T.
    Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% Chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log 10 reduction factor of 1.5, the log10 reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
  • Thumbnail Image
    Item
    On the fundamental relation of laser schlieren deflectometry for temperature measurements in filamentary plasmas
    (Les Ulis : EDP Sciences, 2015) Schäfer, Jan; Bonaventura, Zdeněk; Foest, Rüdiger
    Recently, laser schlieren deflectometry (LSD) had been successfully employed as a temperature measurement method to reveal the heat convection generated by micro filaments of a self-organized non-thermal atmospheric plasma jet. Based on the theory of the temperature measurements using LSD, in this work, three approaches for an application of the method are introduced: (i) a hyperbolic-like model of refractive index is applied which allows an analytical theory for the evaluation of the deflection angle to be developed, (ii) a Gaussian shape model for the filament temperature is implemented which is analyzed numerically and (iii) an experimental calibration of the laser deflection with a gas mixture of helium and argon is performed. Thus, these approaches demonstrate that a universal relation between the relative maximum temperature of the filament core (T1/T0) and a the maximum deflection angle δ1 of the laser beam can be written as T1/T0=(1 − δ1/δ0)−1, where δ0 is a parameter that is defined by the configuration of the experiment and by the assumed model for the shape of the temperature profile.