Electrode Dielectric Barrier Discharge Research Articles

The Efficacy of Floating Electrode-Dielectric Barrier Discharge Plasma against Staphylococcus aureus and Salmonella Typhimurium on Fried Fish Paste

In this study, we evaluated the antibacterial effect of floating electrode–dielectric barrier discharge (FE-DBD) plasma (1.1 kV, 43 kHz, N2 1.5 m/s, 1–60 min) against Staphylococcus aureus and Salmonella Typhimurium in fried fish paste. In addition, a quality evaluation (pH, VBN) of fried fish paste was conducted after the FE-DBD plasma treatment. When FE-DBD plasma was used for treatment for 1, 5, 10, 20, 30, and 60 min, S. aureus decreased by 0.16–1.13 log10 CFU/g, and S. Typhimurium decreased by 0.25–1.13 log10 CFU/g. Both decreased > log10 CFU/g at 60 min. The D-value was 58.92, and R2 was 0.97 for S. aureus using first-order kinetics, and the D-value was 43.60, and R2 was 0.97 for S. Typhimurium using the Weibull model. There was no significant difference in pH after the FE-DBD plasma treatment (p > 0.05). Additionally, volatile basic nitrogen (VBN) significantly decreased as the treatment time increased (p < 0.05), and it was the lowest 3.46 at 60 min. Therefore, this FE-DBD plasma treatment could be considered a technology for preserving the quality of processed foods.

On Encapsulated Dielectric Barrier Discharge Plasma Sources for Radar Cross Section Reduction in Mobile Environments.

This paper deals with the practical application of Radar Cross Section (RCS) reduction technology using plasma. Although various plasma application technologies for RCS reduction have been studied, there are still many issues to be addressed for practical implementation. In order to achieve actual application, the discharge should be sustained regardless of the external environment of the aircraft. It is also important to investigate the actual plasma parameters to determine the expected RCS reduction effect. Building upon previous studies that optimized the electrodes for RCS reduction, this study fabricates a Dielectric Barrier Discharge (DBD) source suitable for dynamic environments and verifies the power consumption during one cycle of plasma generation. The obtained results are expected to contribute to the optimization of DBD electrodes for plasma RCS reduction.

Plasma Electrode Dielectric Barrier Discharge: Development, Characterization and Preliminary Assessment for Large Surface Decontamination

Plasma Electrode Dielectric Barrier Discharge: Development, Characterization and Preliminary Assessment for Large Surface Decontamination

Inclusion of Biological Targets in the Analysis of Electrical Characteristics of Non-Thermal Plasma Discharge

In Plasma Medicine studies, the effect of non-thermal plasma (NTP) on biological targets is typically correlated with the amount of stable reactive oxygen and nitrogen species produced in a liquid medium. The effect of NTP and the response of the biological target on cellular redox mechanisms is overlooked in these investigations. Additionally, the influence of electrical properties of cells on the physical properties of NTP is neglected. Therefore, we used a floating electrode dielectric barrier discharge plasma to explore the impact of cell structure, size, and viability of the biological target on the physical properties of NTP. Lissajous figures were used to determine circuit capacitance and energy per cycle during NTP exposure of different cell suspensions. We show that both, structural integrity and active enzymic processes of cells change the electrical properties of NTP. Correlations were also drawn between NTP-produced hydrogen peroxide and nitrite with measured capacitance. Our studies indicate that the observed changes between different cell suspensions may be due to a feedback loop between the biological target and the NTP source. In future studies, a more detailed analysis is needed to improve the control of clinical NTP devices.

Nonoxidative methane coupling in a micro‐DBD with enhanced secondary electron emission

AbstractThe conversion of methane into transportable and storable materials is crucial in the petrochemical sector. In this study, a specially constructed AC‐driven dielectric barrier discharge (DBD) that has charge injector pyramids on one of the electrodes and runs at ambient temperature and pressure was used to evaluate noncatalytic methane conversion. The obtained result was compared with the traditional flat electrode DBD. It was discovered that the product selectivity in direct nonoxidative methane conversion depended on the discharge conditions. Pyramid electrode plasma sources convert methane up to 50 more than flat electrode plasma due to the appearance of more microdischarges. Pyramid electrode plasma generally has a greater production efficiency than flat electrode plasma, while requiring more operational power. The turnkey solutions offered by the sustainable methane coupling method discussed here may be advantageous for the long‐term small‐scale ethylene exploration scenario.

Novel RDD Pulse Shaping Method for High-Power High-Voltage Pulse Current Power Supply in DBD Application

High-voltage pulse power supplies are key power input devices for the study and application of discharge plasma. A high-voltage pulse current power supply (HV-PCPS) with an energy storage pulse transformer based on flyback topology can output microsecond pulsewidths with high-power, ultrahigh voltage, and high reliability, which are suitable for most dielectric barrier discharge (DBD) plasma applications. However, during the process of DBD driven by an HV-PCPS based on an energy storage pulse transformer, the output pulse voltage waveform quality is poor, making it not suitable for stable discharge long-term operation. This article aims to solve the aforementioned problem and proposes a novel resistor–diode–diode (RDD) shaping method. Not only can this novel method solve the problem of poor quality of the output pulse power from the HV-PCPS, guaranteeing stable discharge for various DBD electrodes, it can also limit the maximum output voltage amplitude. This prevents overvoltage breakdown when the output terminal is in an open state or a light load state because the HV-PCPS is acting as a current source. This article also analyzes the effectiveness of an RDD branch when solving the problem in theory, and gives a detailed parameter design method. Finally, a 30-kV HV-PCPS prototype is built to verify the effectiveness of the proposed RDD pulse shaping method. The average pulse power output of the whole prototype is greatly improved, and it can achieve an average pulse power output of 1 kW. Furthermore, the electrode loads of different DBD reactors can be driven by this technology.

Simulated experiments for removal of odorous gases by wire-mesh electrode dielectric barrier discharge

The emission of odorous gases from various industrial processes such as factories and wastewater treatment, in addition to emissions from landfills and livestock, has become a public concern because of their negative effect on air quality and human health. This study presents a technology based on dielectric barrier discharge (DBD) of wire-mesh type with a high-voltage electric wire as the electrode. This system was used to experimentally assess the removal efficiency of odorous gases. The plasma system consists of a wire electrode with a mesh-type configuration, a small blower (1.6 N m3/min, compressed air) for the plasma discharge or to supply cooling gas, and an AC high-voltage power supply. The plasma system offers the advantages of low power consumption and a large discharge area for ozone production. The wire-mesh electrode DBD comprises 64 discharge nodes, and the large amount of ozone generated from these nodes is used to oxidize odorous gases. Under optimized conditions, ozone is stably generated at the rate of 5.1 g/h for a specific input energy of 3.7 J/L. The ozone and odorous compounds (H2S: 4.5 ppm, CH3SH: 6.7 ppm, NH3: 3 ppm, outlet concentration) are injected into the main blower (20 N m3/min, compressed air). Finally, the experiments designed to simulate the removal of odorous gases confirmed that 99% of odorous compounds were removed using the wire-mesh electrode DBD. The cost-effectiveness and scalability of this system make it highly suitable for use in industrial environments where odorous gases are produced.

Energy Yield and Removal Efficiency of NO x Curtailment Process With High Voltage Pulse Powered DBD Electrode Configurations

Experimental investigation on the NO_<i>x</i> removal efficiency and energy yield (EY) of eight dielectric barrier discharge (DBD) reactor configurations is done in this work. A high voltage pulsed power supply developed in the laboratory is used to generate nonthermal plasma (NTP) in the reactors with eight types of electrodes varying in shape and dimensions. Simulated NO_<i>x</i> gas with a concentration of 350 ppm is passed at a flow rate of 8 l/min through the reactors. Different pulse voltage amplitude and repetition rate are applied to the reactors for generating NTP in the confined airgap. Gas concentrations at the inlet and outlet, applied voltage, and voltage across the monitoring capacitance were measured at each of these operating points. Corresponding discharge power, specific energy density (SED), NO_<i>x</i> removal efficiency, and EY were calculated. NTP treatment without any catalysts/adsorbents attained NO_<i>x</i> removal efficiency of 95&#x0025; and above using screw thread electrode, 5 mm rod electrode, pipe electrode and coiled wire electrode configurations. But considering the discharge power, SED, and hence the EY of the process, DBDs with pipe electrode and wire electrode were found to be effective with lower energy consumption. Based on this observation, the selection of appropriate DBD configuration and electrical input parameters can be made according to the intended EY for a specific process.

Experimental and mechanism research on the NOx removal by a novel liquid electrode dielectric barrier discharge reactor

Metal electrode corrosion and poor discharge uniformity are the key factors that restrict the discharge lifetime and de-NOx efficiency of a dielectric barrier discharge (DBD) reactor. In order to solve this problem, a novel DBD reactor with homothermic sodium chloride (NaCl) solution as grounded electrode was designed in this paper. The effects of NaCl solution conductivity on the electrical parameters, the de-NOx performance and the optical emission spectrum characteristics of DBD were studied experimentally. The pathways and mechanism of de-NOx in the whole discharge phase were revealed by numerical simulation, electron impact mechanism and chemical reactions sensitivity analysis. The results showed that the best discharge intensity, uniformity, energy consumption and de-NOx performance were achieved at 32mS/cm of NaCl solution conductivity. The removal efficiency of NO, NO2 and NOx reached close to 100%, 97.4% and 83.9% respectively. The numerical simulation showed that the de-NOx process of DBD could be divided into 3 phases, including the rapid removal phase of NO (0–0.05 s), the removal phase of NO and NO2 (0.05–0.7 s), and the stabilization phase of NOx (0.7–1 s). In terms of de-NOx mechanism, the active particles of N atoms, N(2D) atoms and O atoms dissociated from exhaust gas played key roles in the de-NOx process. The N atoms mainly reduced NO to pure N2, and the selectivity of N2 could reach up to 13.6%. The N(2D) atoms were the only radicals that formed extra NO. The O atoms contributed greatly with NO2 re-conversion to NO. This work is of great significance to promote the removal of NOx from ship exhaust gas by the DBD with liquid electrode.

Behavior of the Surviving Population of Listeria monocytogenes and Salmonella Typhimurium Biofilms Following a Direct Helium-Based Cold Atmospheric Plasma Treatment.

Although the Cold Atmospheric Plasma (CAP) technology proved promising for inactivation of biofilms present on abiotic food contact surfaces, more research is required to examine the behavior of the CAP surviving biofilm-associated cells. It was therefore examined whether (i) CAP treated (Listeria monocytogenes and Salmonella Typhimurium) biofilm-associated cells were able to further colonize the already established biofilms during a subsequent incubation period and (ii) isolates of the surviving population became less susceptible toward CAP when the number of biofilm development—CAP treatment cycles increased. For this purpose, a direct treatment was applied using a helium-based Dielectric Barrier Discharge electrode configuration. Results indicated that the surviving population was able to further colonize the already established biofilms, since the cell density of the CAP treated + incubated biofilms equaled the initial density of the untreated biofilms. For the L. monocytogenes biofilms, also the total biomass proved to further increase, which might result in an even further increased resistance. The susceptibility of the biofilm-associated cells proved to be influenced by the specific number of CAP treatment cycles, which might potentially result in an overestimation of the CAP treatment efficacy and, consequently, an increased risk of food contamination.

Indoor air quality improvement and purification by atmospheric pressure Non-Thermal Plasma (NTP)

Non-thermal plasma (NTP) is a promising technology for the improvement of indoor air quality (IAQ) by removing volatile organic compounds (VOCs) through advanced oxidation process (AOP). In this paper, authors developed a laboratory scale dielectric barrier discharge (DBD) reactor which generates atmospheric NTP to study the removal of low-concentration formaldehyde (HCHO), a typical indoor air VOC in the built environment associated with cancer and leukemia, under different processing conditions. Strong ionization NTP was generated between the DBD electrodes by a pulse power zero-voltage switching flyback transformer (ZVS-FBT), which caused ionization of air molecules leading to active species formation to convert HCHO into carbon dioxide (CO2) and water vapor (H2O). The impact of key electrical and physical processing parameters i.e. discharge power (P), initial concentration (Cin), flow rate (F), and relative humidity (RH) which affect the formaldehyde removal efficiency (ɳ) were studied to determine optimum conditions. Results show that, the correlation coefficient (R2) of removal efficiency dependence on the processing parameters follow the order R2 (F) = 0.99 > R2 (RH) = 0.96, > R2 (Cin) = 0.94 > R2 (P) = 0.93. The removal efficiency reached 99% under the optimum conditions of P = 0.6 W, Cin = 0.1 ppm, F = 0.2 m3/h, and RH = 65% with no secondary pollution. The study provided a theoretical and experimental basis for the application of DBD plasma for air purification in the built environment.

Simulation of Cold Atmospheric Plasma Generated by Floating-Electrode Dielectric Barrier Pulsed Discharge Used for the Cancer Cell Necrosis

A numerical simulation of a pulsed floating electrode dielectric barrier discharge (FE-DBD) at atmospheric pressure, used for melanoma cancer cell therapy, is performed using a plasma model in COMSOL Multiphysics software. Distributions of electron density, space charge, and electric field are presented at different instants of the pulsed argon discharge. Significant results related to the characteristics of the plasma device used, the inter-electrodes distance, and the power supply are obtained to improve the efficiency of FE-DBD apparatus for melanoma cancer cell treatment. The FE-DBD presents a higher sensitivity to short pulse durations, related to the accumulated charge over the dielectric barrier around the powered electrode. At higher applied voltage, more energy is injected into the discharge channel and an increase in electron density and electric consumed power is noted. Anticancer activity provided by the FE-DBD plasma is improved using a small interelectrode distance with a high electron emission coefficient and a high dielectric constant with a small dielectric thickness, allowing higher electron density, generating reactive species responsible for the apoptosis of tumor cells.

Surface treatment of titanium dioxide nanopowder using rotary electrode dielectric barrier discharge reactor

Titanium dioxide (TiO2) nanopowder (P-25; Degussa AG) was treated using dielectric barrier discharge (DBD) in a rotary electrode DBD (RE-DBD) reactor. Its electrical and optical characteristics were investigated during RE-DBD generation. The treated TiO2 nanopowder properties and structures were analyzed using x-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). After RE-DBD treatment, XRD measurements indicated that the anatase peak theta positions shifted from 25.3° to 25.1°, which can be attributed to the substitution of new functional groups in the TiO2 lattice. The FTIR results show that hydroxyl groups (OH) at 3400 cm−1 increased considerably. The mechanism used to modify the TiO2 nanopowder surface by air DBD treatment was confirmed from optical emission spectrum measurements. Reactive species, such as OH radical, ozone and atomic oxygen can play key roles in hydroxyl formation on the TiO2 nanopowder surface.

Effects of the discharge frequency on the dielectric barrier discharge ignition behaviors for lean methane–air mixtures at various pressure values

An experimental study on dielectric barrier discharge (DBD) plasma-assisted ignition was performed through the use of a plug-type DBD electrode at various pressures p up to 500 kPa. The ignition behaviors of lean methane–air mixtures with high-frequency DBD were investigated near the lean limit in a constant volume chamber. Using a high-speed video camera, the plasma formations of the DBD were observed for air and a mixture of the equivalence ratio ϕ=0.3. Plasma spectroscopy was also conducted with an echelle grating and imaging spectrometers. The time-averaged detailed plasma emission spectra from 400 nm to 920 nm and the transient spectrograms in the vicinity of the N2 second positive system (372–382 nm) for ϕ=0.5 were measured. The minimum ignition energy (MIE), minimum discharge duration, and minimum amplitude of the applied voltage were obtained through logistic regression. The results indicated that a plasma emission lifetime became much longer than the discharge time with an application of the high-frequency sinusoidal voltage at high pressure. The longest plasma lifetime was observed at a discharge frequency of 1,180 kHz. The plasma lifetime showed the maximum at a specific pressure. The detailed spectroscopy also showed that continuum spectra at 500 kPa could be fitted to the Planck's curve with temperature above 3000 K at 500 kPa. The profiles of the MIE as a function of pressure exhibited the minimum in the vicinity of 100 kPa. The existence of the optimal frequency for high-efficiency ignition was shown. At the fixed frequency, an increase in the applied voltage amplitude resulted in a decrease in the MIE. In contrast, the effects were saturated over a certain threshold. At 500 kPa, time-resolved plasma spectroscopy showed a rapid local gas heating to the flame temperature over a specific frequency of the applied voltage. This indicated that there was the optimal frequency where the MIE was the minimum.

Effect of Cold Plasma on the Levels Mineral Blood Components &lt;i&gt;In Vivo&lt;/i&gt;

This study illustrates effect of cold plasma CAP on the mineral blood components in vivo. the mineral blood component (Ca, Na, Cl, K and Fe) are used. Floating Electrode-Dielectric Barrier Discharge (FE-DBD) system of probe diameter 4cm is used for this purpose, and variable voltage (0-20) kV and variable frequency (0-30) kHz, the output power was ranged from (10 - 70) W. the effect of cold atmospheric plasma on mineral blood is studied with different exposure durations (30,45,60) sec. As the plasma exposure duration increases, the calcium, potassium and iron components in the blood increased, while The sodium and chlorine elements decreased. These results give an indication of the cold plasma receptor to be used to treat many diseases related to mineral blood components.

Novel IPOx Architecture for High-Voltage Microsecond Pulse Power Supply Using Energy Efficiency and Stability Model Design Method

The high-voltage microsecond pulse power supply (HV-MPPS) is a key power input device for the study and application of plasma discharge. The energy-storage-based high-voltage pulse power supply outputs microsecond pulsewidths to obtain high-power, ultra-high voltage, and fast front-end output pulses, which are suitable for most plasma discharge applications. However, with the increasing output power requirement of the HV-MPPS, the traditional energy storage type architecture will increase dramatically in volume and weight with lower output efficiency and lower reliability, so it will not be able to achieve optimal electrical performance in plasma discharge applications. This article proposes a design method of energy efficiency and stability model based on the system architecture of IPOx (input parallel output x), where “x” means the output terminal can be in parallel (IPOP) or series (IPOS), in the application field of low-temperature plasma dielectric barrier discharge (DBD) discharge. The optimal multimodule connection mode and the number of modules can be calculated and designed easily according to different DBD electrode structures using energy efficiency and stability model design method. Finally, the proposed energy efficiency and stability model is verified by comparing the electrical experimental results and discharge status photographs of two type DBD electrodes with the 2/3/4 modules IPOx system platform.

Microbial Inactivation by Non-equilibrium Short-Pulsed Atmospheric Pressure Dielectric Barrier Discharge (Cold Plasma): Numerical and Experimental Studies

Microbial inactivation efficacy of plasma generated by a custom-made floating electrode dielectric barrier discharge (FE-DBD) or cold plasma at three different frequencies (1 kHz, 2 kHz, and 3.5 kHz) was experimentally evaluated for its inactivation of the pathogen surrogate Enterobacter aerogenes on a glass surface to obtain inactivation kinetics. COMSOL Multiphysics® was used to numerically simulate the amount and the distribution of reactive species within an FE-DBD system. Microbial inactivation kinetics was predicted using species concentrations and microbial inactivation rates from the literature and compared with experimental data. The results showed that the FE-DBD plasma treatment achieved a microbial reduction of 4.3 ± 0.5 log CFU/surface at 3.5 kHz, 5.1 ± 0.09 log CFU/surface at 2 kHz, and 5.1 ± 0.05 log CFU/surface at 1 kHz in 2 min, 3 min, and 6 min, respectively. The predicted values were 4.02 log CFU/surface, 4.10 log CFU/surface, and 4.56 log CFU/surface at 1 kHz, 2 kHz, and 3.5 kHz, respectively. A maximum 1 log difference was observed between numerical predictions and the experimental results. The difference might be due to synergistic interactions between plasma species, UV component of FE-DBD plasma, and/or the electrical field effects, which could not be included in the numerical simulation.

Effect of a diamond layer on the active electrode on the ozone generation of the dielectric barrier discharge in air

We investigated the effect of a non-doped diamond layer deposition on the active electrode of the dielectric barrier discharge in the air on its electrical characteristics and ozone generation. We found that this new non-traditional application of diamond layers affects electrical parameters of the discharge and increases not only the concentration of ozone produced by the discharge but also ozone production yield by ∼70%. Considering obtained results together with the high corrosion resistivity and chemical inertness of the diamond layers, the application of these layers on the dielectric barrier discharge electrode can be an interesting alternative to the usage of photocatalysts for the enhancement of ozone generation by electrical discharges.

Effect of Cold Atmospheric Pressure Plasma on Fertility Hormones for Female Rats

The direct application of cold atmospheric plasma (CAP) is the main scope of plasma medicine in or on the organism for curative purposes. Cold plasma is both effective in disrupting a wide range of microorganisms including multiple drug resistant ones (MDRs) and to stimulate proliferation of mammalian cells. It has obtained by Floating Electrode Dielectric Barrier Discharge (FE-DBD) system. The present study aimed to show the effected of cold plasma on the fertility hormones LH, Prolactin, Estrogen, and Testosterone hormones for healthy adult female rats (Albino) / bulb c). There are divided into many groups according to time exposure of plasma (15, 30, 60, and 90 second) and a reference group (without plasma exposure), with different time intervals after exposure (1, 2, 3, 7, 14, 28 days). The concentration of hormones was measured using Enzyme Linked Immunosorbent Assay (ELISA). The results showed that, the CAP effected slightly on the Luteinizing Hormone (LH) and Estradiol Hormone (E2) the concentration levels slightly increased and stay near to the reference value for all times. Prolactin hormone (PRL) was effected significantly from the first day after exposure to CAP for all times, it was increased significantly (P < 0.0001) for short time of exposure (15, 30 sec) than control group value, and it was decreased significantly (P < 0.0001) than control value for time of exposure ( 60, 90 sec). The result of testosterone hormone is decreased significantly from the first day after exposure to CAP for all time exposure (15, 30, 60, and 90 sec).

Inactivation of L. monocytogenes and S. typhimurium Biofilms by Means of an Air-Based Cold Atmospheric Plasma (CAP) System.

Previous (biofilm) inactivation studies using Cold Atmospheric Plasma (CAP) focused on helium (with or without the addition of oxygen) as feeding gas since this proved to result in a stable and uniform plasma. In industry, the use of helium gas is expensive and unsafe for employees. Ambient air is a possible substitute, provided that similar inactivation efficacies can be obtained. In this research, 1 and 7 day-old (single/dual-species) model biofilms containing L. monocytogenes and/or S. typhimurium cells were treated with an air-based Surface Barrier Discharge (SBD) plasma set-up for treatment times between 0 and 30 min. Afterwards, cell densities were quantified via viable plate counts, and predictive models were applied to determine the inactivation kinetics and the efficacy. Finally, the results were compared to previously obtained results using a helium-based SBD and DBD (Dielectric Barrier Discharge) system. This study has demonstrated that the efficacy of the air-based CAP treatment depended on the biofilm and population type, with log-reductions ranging between 1.5 and 2.5 log10(CFU/cm2). The inactivation efficacy was not significantly influenced by the working gas, although the values were generally higher for the air-based system. Finally, this study has demonstrated that the electrode configuration was more important than the working gas composition, with the DBD electrode being the most efficient.