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- ItemThe equivalent circuit approach for the electrical diagnostics of dielectric barrier discharges: The classical theory and recent developments(Basel : MDPI AG, 2019) Pipa, Andrei V.; Brandenburg, RonnyMeasurements of current and voltage are the basic diagnostics for electrical discharges. However, in the case of dielectric barrier discharges (DBDs), the measured current and voltage waveforms are influenced by the discharge reactor geometry, and thus, interpretation of measured quantities is required to determine the discharge properties. This contribution presents the main stages of the development of electrical diagnostics of DBDs, which are based on lumped electrical elements. The compilation and revision of the contributions to the equivalent circuit approach are targeted to indicate: (1) the interconnection between the stage of development, (2) its applicability, and (3) the current state-of-the-art of this approach. © 2019 by the authors.
- ItemCorrigendum: Dielectric barrier discharges: progress on plasma sources and on the understanding of regimes and single filaments (Plasma Sources Science and Technology (2017) 26 (053001) DOI: 10.1088/1361-6595/aa6426)(Bristol : IOP Publ., 2018) Brandenburg, RonnyThe paper Dielectric barrier discharges: progress on plasma sources and on the understanding of regimes and single filaments? [1] contains a serious misprint in the section ?Electrical behavior and characterization?. The correct equation (5) for the determination of the gap voltage Ug is as follows (Formula Presented). The second term is the voltage across the barrier (Ub) which is determined by the charge Q t and the capacity of the barrier(s) Cd. The parameter 1 Ccell as written in the original paper is not correct, and a misprint. The sum of gap voltage and barrier voltage equals the applied voltage V t . Detailed explanations about the formula can be found in the cited literature, in particular [2-4].
- ItemDielectric barrier discharges: progress on plasma sources and on the understanding of regimes and single filaments(Bristol : IOP Publ., 2017-3-30) Brandenburg, RonnyDielectric barrier discharges (DBDs) are plasmas generated in configurations with an insulating (dielectric) material between the electrodes which is responsible for a self-pulsing operation. DBDs are a typical example of nonthermal atmospheric or normal pressure gas discharges. Initially used for the generation of ozone, they have opened up many other fields of application. Therefore DBDs are a relevant tool in current plasma technology as well as an object for fundamental studies. Another motivation for further research is the fact that so-called partial discharges in insulated high voltage systems are special types of DBDs. The breakdown processes, the formation of structures, and the role of surface processes are currently under investigation. This review is intended to give an update to the already existing literature on DBDs considering the research and development within the last two decades. The main principles and different modes of discharge generation are summarized. A collection of known as well as special electrode configurations and reactor designs will be presented. This shall demonstrate the different and broad possibilities, but also the similarities and common aspects of devices for different fields of applications explored within the last years. The main part is devoted to the progress on the investigation of different aspects of breakdown and plasma formation with the focus on single filaments or microdischarges. This includes a summary of the current knowledge on the electrical characterization of filamentary DBDs. In particular, the recent new insights on the elementary volume and surface memory mechanisms in these discharges will be discussed. An outlook for the forthcoming challenges on research and development will be given.
- ItemAbout the Development and Dynamics of Microdischarges in Toluene-Containing Air(Dordrecht : Springer Science + Business Media B.V., 2019) Brandenburg, Ronny; Jahanbakhsh, Sina; Schiorlin, Milko; Schmidt, MichaelThe development of microdischarges and the inception dynamics of subsequent microdischarges in an electrode arrangement consisting of a metal pin and a hemispherical dielectric-covered electrode, operated in air with a small toluene admixture, is studied. The discharge is operated with sinusoidal high voltage. A gated ICCD camera and a current probe enable the recording of images and current pulses of the single microdischarges, respectively, while the spatio-temporally resolved development is measured with a multi-dimensional time-correlated single photon counting technique. The overall discharge dynamics changes significantly if a concentration of 35 ppm toluene is added to dry air. A lower high voltage amplitude than in dry air is needed for stable discharge operation. This can be explained by the lower ionization energy of toluene compared to molecular oxygen and nitrogen. The microdischarge development is the same with or without admixture, i.e. a positive (cathode directed) streamer mechanism is observed. Lower mean power is dissipated into the discharge when toluene is admixed. The main effect caused by toluene admixture is the suppression of high-energy microdischarges in case of the cathodic pin half-cycle of the sinusoidal high voltage. The influence on the inception voltage by additional ionization mechanisms and volume memory effects, the consumption of energetic electrons for toluene decomposition reactions, and the modification of the surface by plasma treatment are discussed as possible reasons.
- ItemStudies on the Electrical Behaviour and Removal of Toluene with a Dielectric Barrier Discharge(Berlin : de Gruyter, 2014) Schmidt, Michael; Schiorlin, Milko; Brandenburg, RonnyThis contribution attempts to establish an easy-to-apply non-thermal plasma reactor for efficient toluene removal. Derived from the already established knowledge of the so called Dielectric Barrier Discharge (DBD) Stack Reactor a new model reactor was used in this work. The DBD Stack Reactor is a multi-elements reactor but in this work only one stack element was used to investigate the efficiency and efficacy of toluene removal. In case of reliable results the scalability process for industrial application is already well known. Therefore, laboratory experiments were conducted in dry and wet synthetic air with an admixture of 50 ppm toluene. Along with the toluene removal process the electrical behaviour of the discharge configuration was investigated. It was found that the electrical capacitance of the dielectric barrier changes with variations of the operating voltage. This could be due to the changes in the area of the dielectric barrier which is covered with plasma. Additionally, it was found that the power input into the plasma, at a fixed operating voltage, is proportional to the frequency, which is in agreement with the literature.Regarding the decomposition process, the total removal of toluene was achieved at specific input energy densities of 55 J L-1 under dry conditions and 110 J L-1 under wet conditions. The toluene removal was accompanied by the production of nitric acid (dry conditions) and formic acid (wet conditions). The latter suggested a combination of the plasma reactor with a water scrubber as an approach for total removal of pollutant molecules.
- ItemInnoPlas - Innovative Atmosphärendruck-Plasmaprozesse für industrielle Anwendungen : Schlussbericht ; Pilotprojekte: ConPlas - plasmagestützte Dünnschichten, PLexc - plasmagestützte Lackierungen, ProTool - Entwicklungswerkzeuge zur Optimierung von Plasmaverfahren und -quellen ; ForMaT2(Hannover : Technische Informationsbibliothek (TIB), 2011) Brandenburg, Ronny; Horn, Stefan; Krohmann, Udo; Rackow, Kristian; Uhrlandt, Dirk; Witt, Göran; Weltmann, Klaus-Dieter[no abstract available]