Electrical and chemical properties of the

The purpose of this paper is to study, through numerical modeling, the \chem{XeCl} kinetics and the mechanisms affecting plasma uniformity in high-pressure discharge pumped excimer lasers. In the model, the plasma is represented by a resistance inversely proportional to the electron density. Time variation of the electron density is obtained by integrating the transport equations coupled to the heavy-species kinetics and to the external circuit. A detailed description of the \chem{XeCl} molecule and of the associated kinetics has been taken into account, together with the effect of the gas mixture composition on power deposition and the spatial uniformity of the plasma. Calculated discharge current and voltage are compared with experimental results. The obtained results indicate clearly that about 50% of the halogen is consumed at the end of the discharge pulse

Characterization and study of the transfer of PAHs in karstic medium of mid-mountain: Case of the forest of Hafir - Tlemcen (Western Algeria)

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Physico-Chemical Investigation of Pulsed Discharge in CO<SUB>2</SUB>/O<SUB>2</SUB> Gas Mixture

International audienceIn this research, the decomposition of CO2 inCO2/O2 pulsed discharge was studied. The developedmodel is based on the physical processes involved in the discharge withthe CO2 plasma chemistry, the electrical circuit, and theBoltzmann equations. The fundamental chemistry ofCO2/O2 gas mixture used in this work is based on afull set of processes regrouped in 113 reactions involving 21 species ofthe discharge. The obtained numerical results show the temporalvariations of electrical parameters and species concentrations of thedischarge. We have also studied the effect of some discharge parameters(gas pressure, dielectric capacitance, applied voltage, concentration ofO2 in CO2/O2 gas mixture, andfrequency) on the discharge behavior

One-dimensional modelling of DBDs in NeXe mixtures for excimer lamps

International audienceDielectric barrier discharges (DBDs) are a promising technology for high-intensity sources of specific UV and VUV radiation. In this work, the microdischarge dynamics in DBDs for Ne−Xe mixtures under the close conditions of excimer lamp working has been investigated. The computer model including the cathode fall, the positive column and the dielectric is composed of two coupled sub-models. The first submodel describes the electrical properties of the discharge and is based on a fluid, two-moments description of electron and ion transport coupled with Poisson's equation during the discharge pulse. The second submodel, based on three main modules: a plasma chemistry module, a circuit module and a Boltzmann equation module, with source terms deduced from the electric model, describes the time variations of charged and excited species concentrations and the UV photon emission. The use of the present description allows a good resolution near the sheath at high pressure and it predicts correctly the waveform of the discharge behavior. The effects of operation voltage, dielectric capacitance, gas mixture composition, gas pressure, as well as the secondary electron emission by ion at the cathode on the discharge characteristics and the 173 nm photon generation have been investigated and discussed

Investigation of the development of dielectric-barrier discharge instabilities in excimer lamp

International audienceThis work represents a study of the formation and propagation of the streamer during a pulse in a plasma cell with dielectric barriers containing a Ne/Xe gas mixture. It is based on a longitudinal mono-dimensional model of the dielectric barrier discharge. In this model, we show the possibility of streamers development in the cathode sheath and its propagation during the plasma formation stage. The model gives the spatiotemporal variations of the propagation speed, the electric field, and the charged particle density of the streamer's head

Metal ions sorption on insoluble ferrocyanides and other sorbent materials.

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Theoretical Kinetics Investigation of Krypton Dielectric Barrier Discharge for UV Lamp

International audienceThis work presents an electric and kinetic study of homogeneous dielectric barrier discharge (DBD) in pure krypton (Kr). The electrical characterization and kinetic analyses of the DBD in Kr are performed. The plasma formation in DBD, excited by sinusoidal voltage at high pressure, was studied. The discharge development, with homogeneous model approach and using extended kinetic scheme, is simulated. The study is based on a spatial homogeneity model including the plasma chemistry, the electrical circuit and the Boltzmann equations’. The temporal variations of discharge voltage, dielectrics voltage, discharge current, electric field and species concentrations are calculated. The plasma kinetics is discussed with the aim to finding the optimal efficiency. The photon generation, under typical operating conditions, was investigated and discussed. The effect of some parameters on the excilamp like pressure, applied voltage, and frequency are investigated in order to identify the optimal parameters for maximum luminous efficiency in the UV range