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Aims The worldwide spread of the coronavirus SARS-CoV-2 has highlighted the need for fast and simple disinfection processes, amongst others for ambulance cars on site. To overcome current drawbacks regarding room disinfection, the use of cold atmospheric plasma in remote operation represents a promising alternative for the disinfection of larger volumes. In this study, a compact plasma system was evaluated regarding its disinfection efficiency inside an ambulance car. Methods and Results The developed plasma device is based on a dielectric barrier discharge (DBD) and operates with ambient air as process gas. The humidified afterglow from the plasma nozzle was introduced into an ambulance car with a volume of approximately 10 m3 while Bacillus atrophaeus endospores, Staphylococcus aureus or Phi 6 bacteriophages dried on different surfaces (PET-films, glass slides or aluminum foil) were exposed to the reactive gas inside the ambulance vehicle at eight different positions. Reductions of spores by more than 4 orders of magnitude were found on all surfaces and positions within 2 h. Due to their higher susceptibility, Phi 6 bacteriophages and S. aureus counts were reduced by at least 4 orders of magnitude within 30 min on all surfaces. Conclusion The results show that different microorganisms dried on variable surfaces can be inactivated by several orders of magnitude inside an ambulance by plasma gas from of a compact DBD plasma nozzle. Significance and Impact of the Study Plasma gas generated on site by a DBD plasma nozzle proved to be highly efficient for the disinfection of the interior of an ambulance car. Compact plasma systems could be a viable alternative for the disinfection of vehicles or rooms.

The functionalization of polyester fabric (PES) with antimicrobial agents presents huge number of potential applications in advanced products. However, the lack of functional groups and the high PES hydrophobicity make the functionalization processes costly, prolonged and requires the use of polluting chemical compounds. In this work, dielectric barrier discharge (DBD) plasma treatment, an affordable and environmental-friendly method, was used to introduce new chemical groups, increase the surface energy and roughness of PES in order to improve the adhesion of silver nanoparticles (AgNPs) in its surface. The PES functionalization was evaluated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and antimicrobial efficacy against Staphylococcus aureus and Escherichia coli. Despite some additional oxidation, the DBD plasma- treated PES showed superior adhesion of AgNPs and excellent antimicrobial efficacy even after 10 washing cycles (WC)., (undefined)

Transition-metal phosphides have been of concern as efficient electrocatalysts for oxygen evolution reaction (OER) due to its high conductivity and earth-abundance reserves. However, oxide overlayers formed on their surface by spontaneously atmospheric oxidation are usually neglected, thus confusing the establishment of structure–performance relationship. Herein, we successfully etched the oxide overlayers of NiFe phosphide (NiFeP) by a dielectric barrier discharge (DBD) plasma technique, aiming to reveal the influence of the oxide overlayers on its electrocatalytic performance for OER. It is found that etching the oxide overlayers can accelerate the surface reconstruction process of NiFeP and facilitate the formation of metal hydroxides, which are key intermediate phases for OER. Consequently, the etched NiFeP-DBD material shows remarkably enhanced OER activity with an overpotential of 265 mV at a current density of 10 mA/cm2. The finding of this work probably brings a significant impact to understand the structure–performance relationship of metal phosphide in electrooxidation reaction.

Quasi-static and dynamic stall control experiments, using dielectric barrier discharge plasma actuators, were performed on a square-tipped aspect-ratio-one wing, with a NACA 0015 profile, under harmonic pitching, at a Reynolds number of 3×105. Relatively low 풪(1) and relatively high 풪(10) pulse-modulated reduced excitation frequencies were introduced at the leading edge; the former produced the largest poststall lift improvements, whereas the latter produced the highest maximum lift. A reduced frequency, based on laminar separation bubble shedding, was enlisted to explain the differences between the two results. Under conditions of dynamic pitching, evidence of a dynamic stall vortex was absent, due to its interaction with the strong tip vortices, consistent with prior experimental and numerical investigations. As a general rule, performance benefits produced by excitation under quasi-static conditions were reproduced under harmonic pitching. Low-order dynamic stall and dynamic stall control models, based on a modified version of the Goman–Khrabrov delta-wing concept, were evaluated. Model constants were obtained from quasi-static data sets, and a single baseline dynamic case was employed to determine the time constants. The model produced excellent results for both baseline and controlled cases, which was attributed to similar lift and stall mechanisms exhibited by delta and rectangular low-aspect-ratio planforms.

Flow control effects of three types of nanosecond (NS) dielectric barrier discharge (DBD) plasma actuations in suppressing the flow separation of a compressor airfoil at low Reynolds number are inv...

The spatial–temporal evolution of coherent structures generated by an asymmetrical dielectric barrier discharge (DBD) plasma actuator is an intriguing unsteady process with profound implications fo...

DBD-catalytic system has been widely studied for volatile organic compounds abatement, whereas how to obtain high mineralization rate and low zone emission synchronously remains a challenge. In view of this, a new type of multi-stage DBD-catalytic system (MS1) was established to abatement toluene in this study. The mineralization rates of reactors IPC (63.81%) and MS1 (61.14%) were much higher than MS2, PPC1 and PPC2 reactors, which were 48.36%, 46.84%, and 5.8% at 33.8 (Vp-p) kV, respectively. For export ozone concentration, IPC reactor had the highest concentration of 160 ppm, and the values of reactors MS1, MS2, PPC1, and PPC2 were 79, 34.2, 34.25 and 29 ppm, respectively. The catalyst filled in zone II can be utilized to further decompose the residual toluene and intermediates and also promote the decomposition of ozone, which lead to the superior performance of the MS1 reactor. The influence of applied voltage, adsorbed amount, and discharge time on the toluene removal performance was investigated to optimize the operation parameters of MS1 reactor, their appropriate values were 28.3–31.1 (Vp-p) kV, 0.179–0.223 mmol, ∼1 h, respectively. Lastly, the contribution of disparate zones in multi-stage DBD-catalytic system to the toluene degradation were elucidated on the basis of the GC–MS results.

The dielectric barrier discharge (DBD) is one of the most used low temperature plasma sources. Its industrial and biomedical applications are numerous. In this paper first the history of the development of the DBD is recounted and then its use in biomedical applications is discussed with a focus on biological decontamination. Recent events and challenges related to food contamination, chronic wound infections, rise in antibiotic resistance, and viral driven pandemics have revealed the potential importance of this cold plasma application.

The effect of the surface conductivity on the electrical and mechanical characteristics of the surface dielectric barrier discharge actuator has been numerically investigated in this study. Two typical AC-surface dielectric barrier discharge actuators, wire-to-plate and plate-to-plate have been considered to control airflow alongside a flat dielectric plate. A sinusoidal high voltage of varied frequencies and amplitudes is supplied to the active electrode, and the passive electrode, which is grounded, is encapsulated inside a dielectric plate. Two-species ion transport model, involving generic positive and negative ions, coupled to the electrostatics model is assumed. The electrostatic field is affected by both the space and the surface charges. The surface charge is accumulated due to ion deposition, but its distribution varies due to the surface ohmic conduction. The Navier-Stokes equations for the flow simulation, which include the time-averaged electrohydrodynamic body force determined from the discharge model, are solved to analyze the flow field and the boundary layer morphology. The numerical algorithm has been implemented in the COMSOL commercial package. The significance of the dielectric surface conductivity on the discharge behavior and the flow field has been shown. The dielectric surface conductivity behaves non-monotonically and affects the flow field by altering the EHD force strength, direction and distribution.

Catalytic ammonia (NH3) decomposition has been identified as a COx-free, sustainable hydrogen production method for fuel cell applications. In this study, the performance of plasma–catalyst-based NH3 decomposition over ruthenium (Ru/Al2O3) and soda glass (SiO2) catalytic materials at atmospheric pressure and ambient temperature was investigated. NH3 decomposition reactions were conducted in a dielectric barrier discharge plasma plate-type reactor. NH3 was fed into the plate catalytic microreactor at flow rates of 0.1–1 L/min and plasma voltages of 12–18 kV. Compared to plasma NH3 decomposition without a catalyst, plasma–catalyst-based NH3 decomposition showed a significant enhancement of the hydrogen production rate and energy efficiency. Furthermore, the hydrogen concentration results obtained over the Ru/Al2O3 catalyst were higher than those over the SiO2 catalyst because Ru/Al2O3 possesses good electronic properties and exhibits high sensitivity to NH3 decomposition. In addition, the resulting plasma heat enhanced the activation of the catalytic material, subsequently leading to an increase in the hydrogen production rate from NH3. The maximum conversion rates were 85.65% and 84.39% for Ru/Al2O3 and SiO2, respectively. Moreover, the energy efficiency of NH3 decomposition over the Ru-based catalyst material was higher than that over the SiO2 material. The presence of the catalyst active sites and plasma enhanced the mean electron energy, which could enhance the dissociation of NH3. It can be concluded that the SiO2 material can be utilised as a catalyst and that its combination with plasma accelerates the decomposition process of NH3 and incurs a lower cost compared to Ru materials.

The wind tunnel experiments of separation flow control by a nanosecond-pulse-driven dielectric-barrier-discharge plasma actuator (ns-DBDPA) for three airfoil shapes of NASA-Common-Research-Model (N...

In this work, a combination of synthesized zeolite with a Dielectric Barrier Discharge (DBD) air plasma reactor was applied for the removal of tetracycline (TC) from effluents. The zeolites with different Na2O/SiO2 ratios were synthesized and inserted in a DBD reactor. The as-prepared zeolites were characterized by FTIR, SEM, BET, EDX, XRD, and TEM. The XRD results showed that the P-type zeolite turned to Y-type zeolite with an increasing Na2/SiO2 ratio from 0.5 to 1.5 and 2.5. The TC degradation experiments indicated that 79.1% of the initial TC was removed from the solution by the hybrid plasma- zeolite (Na2O/SiO2 ratio of 0.5) system after 45 min. The plasma in synergy with zeolite caused the changing amount of long-life oxidants in the system and converted it to higher reactive species. The combined system could reduce around 17 and 10% of the total organic carbon (TOC) and chemical oxygen demand (COD) more than the sole DBD system, respectively. Losing just 8% of the initial efficiency of the hybrid system after four successive runs revealed the stability of the proposed system. The radical trapping experiment method indicated that the role of •OH in the TC degradation was more critical than that of O2•−.

Ammonia synthesis at 533 K and atmospheric pressure was investigated in a coaxial dielectric barrier discharge (DBD) plasma reactor without packing and with porous γ-Al2O3, 5 wt % Ru/γ-Al2O3, or 5 ...

ZrO2 was combined with dielectric barrier discharge plasma for hydrolysis of urea under ambient conditions. Effects of discharge power, O2 presence in carrier gas, repeated use of ZrO2 on hydrolysi...

The increase of CO2 concentration in the atmosphere has brought serious greenhouse effects and environmental problems, so it is urgent to solve the problem of excessive CO2 concentration. The carbon capture, utilization, and storage technology refer to the use of CO2 as a C1 resource to generate new economic benefits in a new production process. In this work, the influence of adding different proportions of N2 and Ar to the CO2 gas on the discharge characteristics and reaction performance was investigated with a newly designed dielectric barrier discharge (DBD) micro-plasma segmented electrode reactor and optical emission spectroscopy. The results indicated that the discharge current value increased when the added N2 content was less than 50%, and decreased when the N2 content exceeded 50% under the condition of constant input power. The number and the current value of mixed gas micro-discharges showed a decreasing trend with the increase of Ar content. In the discharge system, the dielectric capacitance (Cd) and the gas gap capacitance (Cg) showed opposite trends with the increase of N2 and Ar content. The dielectric capacitance decreased and the gas gap capacitance increased as the N2 content increased, while the trend was just the opposite as the Ar content increased. In addition, adding a small amount of N2 and Ar was conducive to the conversion of CO2, but when the N2 and Ar content exceeded 50%, the amount of CO2 converted will be reduced.

This work reports an investigation of the discharge characteristics of atmospheric dielectric barrier discharge (DBD) plasma in terms of I-V curves and Lissajous figures and their effect on the surface functionalities of electrospun silk/PVA nanofibers. The results show that the filamentary discharge is predominant at lower electrode gap (3 mm) and then significantly reduces at higher electrode gaps of 6 mm and 10 mm, respectively and in the applied voltage range of 11–17 kV. The silk/PVA nanofibers which are treated with 6 mm electrode gap shows good wettability, higher surface energy, higher tensile strength, young’s modulus values and improved anti-thrombogenic property. All these findings suggest that, although the silk/PVA nanofiber itself can be used in biomedical applications however, nanofibers plasma treated at 6 mm electrode gap shows better results in terms of physical and biological performances.

This article presents a new type of microwave-induced atmospheric-pressure low-temperature dielectric barrier discharge source, based on the principle of parallel plate transmission lines (PPTLs). This source is a simple structure with small size, large plasma discharge area, and low discharge temperature. Experiments show that linear plasma discharge with width of 15 mm can be obtained with input power of only 25 W at 2.45 GHz. The temperature of sample placed 1 mm vertically away from the nozzle and treated for 3 min is about 45 °C even with 60-W microwave input power, which proved its thermal safety even for the biomedical applications. Emission spectroscopy diagnosis indicates that the electron density of plasma can be controlled easily by adjusting the discharge gap and the dielectric thickness. It makes this source available for various applications. This work provides a new approach to obtain uniform linear plasma.

Dyes, a kind of visible chemical, have severe deleterious effects on human health and ecological environment. In this work, batch biosorption experiments were carried out under various experimental conditions such as pH value and agitation time to optimize the potentiality of Enteromorpha prolifera for the removal of malachite green (MG) dye from aqueous solution (70·7%). Then, the algal biomass was treated with a dielectric barrier discharge (DBD) in helium for 4 and 10 min to enhance MG removal efficiency (84·7 and 96·6%). In addition, Fourier-transform infrared spectroscopy in combination with scanning electron microscopy was employed to monitor the chemical and physical changes of algal cells treated by DBD. This study illustrates that DBD may serve as an effective tool to activate the functional groups on the cell wall surface for dye binding, and it even offers an alternative new technique to improve the adsorption properties of native biosorbents for the removal of toxic dyes from wastewater.

The high global warming potential (GWP) of sulfur hexafluoride (SF6) pushed the researcher to find an alternative environmentally friendly gas for high voltage applications. Trifluoroiodomethane (CF3I) has attracted a great deal of attention as new insulation gases. This article has investigated the use of CF3I in dielectric barrier discharge (DBD) based on a 1-D model. Three symmetric waveforms named sinusoidal, triangular, and the clipped waveform was used as a feeding voltage with a frequency of 5 kHz and amplitude of 5 kV. The obtained results revealed that the discharge current consists of many sequential current pulses at each half of the applied voltage and the number of these pulses depends on the waveform of the applied voltage. The discharge current pulses are identical during the positive and negative halves of the applied voltage which refer to the CF3I providing a stable DBD discharge regardless of the polarity of the applied voltage. The first discharge current peak moment, for each waveform and during each half of the cycle, has been selected as the characteristic parameter to investigate the discharge characteristics. At the moment of the first current peak, for all tested waveforms, the results showed that the spatial distribution of the electric field across the gap takes a shape of the letter V referring to the minimum point of the electrical field inside the discharge gap dividing the gap to electronegative and electropositive parts.

In recent years, pulsed discharges at atmospheric pressure have attracted extensive attention due to their remarkable discharge advantages. In this article, a fluid model is applied to investigate a new type of pulsed dielectric barrier discharge (DBD), characterized by a sharp rising phase and slow falling phase but without a plateau phase, which could be realized by using a circuit composed of a device called silicon diode for alternating current (SIDAC). Based on the computational data, the influences of voltage waveform on the plasma density and electric field are carefully discussed. The simulation results show that only one significant discharge event occurs during the voltage rising phase, which produces a large electron density with high electron temperature, but the secondary discharge current cannot be observed due to the slow voltage falling phase. We also qualitatively investigate the effects of discharge parameters on the plasma dynamics, such as the relative permittivity, barrier thickness, and repetitive frequency from simulation data, which agree well with the experimental observation. Based on the simulation results, the optimization of this pulsed discharges to enhance the electron density and improve the electron temperature is discussed, thus promoting the wide applications of the pulsed discharges.

To understand the fundamental physics of dielectric barrier discharge (DBD) actuator array for flow control, the flowfield induced by two successive DBD actuators is investigated under burst-mode a...

A single step ultrasonic biosynthesis method was used to synthesize and coat TiO2 nanoparticles onto DBD plasma functionalized raw cotton. Titanium isopropoxide was reduced with aloe vera plant extract into TiO2 nanoparticles. The effect of DBD plasma treatment on self-cleaning property of TiO2 coated fabric was optimized statistically by using a complete composite design. To induce functional groups on the cotton fabric surface, the fabric was pre-treated with DBD plasma over various periods of time. The plasma exposure time, molarity of solution and ultrasonication time were optimized using complete composite design package. TiO2 nanoparticles revealed spherical shape and anatase phase with average crystallite size of 10.46 nm. The statistically optimized plasma exposure time, molarity and sonication time was 7 min, 0.80 and 75 min, respectively. The plasma activation of fabric significantly improved the adsorption, tensile strength and self-cleaning ability of TiO2 coated fabric.

Nitrogen activation, especially dissociation (production of atomic nitrogen), is a key step for efficient nitrogen fixation, such as nitrogen reduction to produce ammonia. Nitrogen reduction reactions using water as a direct hydrogen source have been studied by many researchers as a green ammonia process. We studied the reaction mechanism and found that the nitrogen reduction could be significantly improved via efficient production of atomic nitrogen through electric discharge. In the present study, we focused on packed-bed dielectric barrier discharge (PbDBD) using dielectric beads as the packing material. The experimental results showed that more atomic nitrogen was produced in the nitrogen activation by the discharge in which the discharge space was filled with the dielectric beads than in the nitrogen activation by the discharge without using the dielectric beads. Then, it was clarified that the amount of atomic nitrogen increased as the dielectric constant of the beads to be filled increased, and the amount of atomic nitrogen produced increased up to 13.48 times. Based on the results, we attempted ammonia synthesis using water as a direct hydrogen source with the efficiently generated atomic nitrogen. When the atomic nitrogen gas generated by the PbDBD was sprayed onto the surface of the water phase and subsequently reacted as a plasma/liquid interfacial reaction, the nitrogen fixation rate increased by 7.26-fold compared to that when using the discharge without dielectric beads, and the ammonia production selectivity increased to 83.7%.

In this paper, the power characteristics and power factor optimization were investigated in a coaxial tube-tube dielectric barrier discharge (DBD) reactor. The effects of several parameters, including discharge voltage, discharge length, discharge frequency and gas flow rate on discharge power and power factor have been evaluated. The experiment results showed that higher discharge power can be obtained by increasing the discharge voltage, discharge frequency and electrode length. But for the power factor, with the increase of discharge frequency, the power factor increased firstly and then decreased. Moreover, with the discharge length increased, the discharge frequency when the power factor reached the maximum value reduced. The response surface method (RSM) and artificial neural network (ANN) were used to optimize the power factor, and their results were relatively consistent. The result of the ANN showed that when discharge voltage was 9.58 kV, discharge frequency was 8.69 kHz, discharge length was 15.8 cm, and gas flow rate was 1.5 L/min, the power factor reached the maximum value of 0.362. The degradation experiment of toluene was carried out in the reactor and its degradation effect was analyzed. The toluene degradation rate is positively correlated with the power factor, and the discharge voltage, gas flow rate and initial concentration are also the key parameters to determine the degradation of toluene. When the discharge voltage, gas flow rate, and initial concentration are 10 kV, 70 mL/min, and 50 ppm, respectively, the power factor and toluene degradation rate reach 0.34 and 74.3%.

As an emerging nonthermal technology, cold plasma has been used to inactivate endogenous enzymes that are responsible for enzymatic browning reaction of fruits and vegetables. This study aimed to investigate the inactivation effect of dielectric barrier discharge (DBD) plasma on horseradish peroxidase (HRP), a typical plant peroxidase. The results showed that DBD plasma caused inactivation of HRP in a time-and discharge power-dependent manner. The HRP activity decreased by 32.5, 50.6, 65.5, and 75.4%, respectively, after 2, 4, 6, and 8 min of exposure to DBD plasma at 57.6 W. The efficacy of DBD plasma for HRP inactivation was enhanced on increasing the discharge power from 6.0 to 57.6 W. Intrinsic fluorescence spectra showed that DBD plasma induced obvious structural changes in HRP. DBD plasma also caused fragmentation and carbonylation of HRP as well as the oxidative degradation of heme, which might be due to the reactive species in plasma. After DBD plasma exposure at 43.0 W for 8 min, there was approximately an 8.4-fold increase in surface hydrophobicity of HRP. After exposure to DBD plasma, the aggregation of HRP was observed by using atomic force microscopy analysis. In conclusion, DBD plasma causes structural changes and chemical modification of HRP, which may be responsible for the loss of enzymatic activity. These data contribute to the application of cold plasma in the control of enzymatic browning of food products during processing and storage.

This study is focused on influence of dielectric barrier discharge (DBD) plasma on surface functionality and coating properties of cotton fabric ultrasonically coated with zinc oxide nanoparticles. Zinc ions were reduced to zinc oxide with Aloe vera leaf extraction and simultaneously coated over plasma-functionalized fabric in an ultrasonic bath. The pad dry method was used for multiple coating cycles. The electron temperature in DBD zone was measured about 1.34 eV. The emission spectrum of DBD revealed the formation of OH−, N2, O, O3, NO, $${\text{N}}_{2}^{ + }$$ , $${\text{O}}_{2}^{ + }$$ and O+ radicals in the discharge zone. The coated fabric was tested for its resistance to the growth of E. coli bacteria, which determines its applications in medical products. The electrical conductivity of fabrics after 2, 4 and 6 pad dry cycles was 2.56 $$\times$$ 10–2, 2.61 $$\times$$ 10–2, and 2.69 $$\times$$ 10–2 Siemens/cm, respectively. The increased conductivity of fabric on coating suggests the growth of a UV protective layer of ZnO nanoparticles on the surface of the fabric. The transmittance of UV-A radiations from blank and ZnO-coated fabrics was measured about 18.42% and 0.89%, respectively. Similarly, UV-B transmittance from blank and ZnO-coated fabrics was measured about 8.41% and 0.29%, respectively. The low UV transmittance and high UV protection factor reveal high practical value of ZnO-coated fabrics.

Numerous reports have elucidated different methods for treating dyeing wastewater using UV irradiation, ozonation, and chlorination. However, the high operational costs of these methods have necessitated the use of plasma. In this study, dielectric barrier discharge (DBD) was used to purify dyeing wastewater, generating ozone as a byproduct. An underwater DBD plasma system was designed to directly interact with water, thereby producing reactive oxygen species (ROS) and functioning as a powerful oxidizer. Additionally, UV, O3, and H2O2 are generated by the developed plasma system without using any other additives to produce OH radicals for purifying organic pollutants; therefore, this system circumvents the use of complex and advanced oxidation processes. A simulation test was performed, which revealed that methylene blue and rhodamine B were completely removed within 7 and 3 min, respectively. Therefore, the developed plasma system can be successfully applied for the purification of dyeing wastewater.

Electrical models can play a crucial role in the characterization, design, and definition of optimal operating conditions of nonthermal plasma sources in a wide field of applications. Various electrical models are available from the literature, with most modeling the behavior of volume dielectric barrier discharge (DBD) plasma sources. Although electrical models for surface DBD plasma sources are presented from the plasma actuator community, these models are limited to simple and mostly linear surface DBD plasma sources. This study presents a new electrical model focusing on surface DBD plasma sources with complex electrode designs. The proposed model employs the ratio of the electrode surface into a discharging and nondischarging area to consider complex electrode designs, such as meshed and hexagonal electrodes. Microdischarges during plasma ignition phase have been modeled through the superposition of a discharge current to the displacement current. The proposed electrical model has been validated over a large range of operating conditions. It is shown that the simulated electrical characteristics using the developed model are in reasonable agreement with measurements.

Producción Científica, Atmospheric cold plasma (ACP) is a non-thermal technology whose ability to inactivate pathogenic microorganisms gives it great potential for use in the food industry as an alternative to traditional thermal methods. Multiple investigations have been reviewed in which the cold plasma is generated through a dielectric barrier discharge (DBD) type reactor, using the atmosphere of the food packaging as the working gas. The results are grouped into meats, fruits and vegetables, dairy and lastly cereals. Microbial decontamination is due to the action of the reactive species generated, which diffuse into the treated food. In some cases, the treatment has a negative impact on the quality. Before industrializing its use, alterations in colour, flavour and lipid oxidation, among others, must be reduced. Furthermore, scaling discharges up to larger regions without compromising the plasma homogeneity is still a significant difficulty. The combination of DBD with other non-thermal technologies (ultrasound, chemical compounds, magnetic field) improved both the safety and the quality of food products. DBD efficacy depends on both technological parameters (input power, gas composition and treatment time) and food intrinsic properties (surface roughness, moisture content and chemistry).

Zearalenone (ZEA) is a mycotoxin that contaminates cereals and grains. Atmospheric cold plasma (ACP) is a novel non-thermal technology that has the potential to degrade mycotoxins. This study evaluated the potential of ACP and the influence of some of the important product and process factors on the degradation of ZEA. The efficacy of 30 s dielectric barrier discharge (DBD) ACP treatment to degrade ZEA in solution and dry condition was 100% and 66.8%, respectively. The ZEA degradation was influenced by the product substrate as the ZEA degradation rates after 3 min DBD-ACP treatment on canola grain, canola meal, and barley grains were 91.6, 83.2, and 64.8%, respectively. Treatment using light pulses (395 nm wavelength) emitted from light-emitting diodes (LED) for 30 min and thermal treatment at 80 °C for 25 min did not exhibit any synergistic effect with ACP on ZEA degradation. The ZEA degradation rates were not significantly different (p > 0.05) when air and 100% N2 were used to generate the ACP by DBD. Treatment by ACP jet using 85% Ar + 15% O2 resulted in the highest degradation of ZEA compared to other gas mixtures used. The results of ZEA degradation using ACP jet, DBD-ACP, and different gas mixtures indicated that there could be contributions from factors other than the measured reactive species, such as UV light and high-energy electrons on ZEA degradation.

Considering that packing dielectric materials into the discharge region of a dielectric barrier discharge reactor tends to cause the increase of undesired gas flow resistance and heating effect, herein, we design a combined system (HD-ZnO) of dielectric materials and discharge by integrating a thin ZnO coating into a hybrid discharge (HD) reactor (instead of packing) for effectively synthesizing ozone (O3) from oxygen (O2). Using the thin ZnO coating makes O3 concentration and production yield of HD respectively increased by an average of 28% and 26% with discharge power of 0.4–3.3 W under the optimum conditions, and also avoids the shortcomings of the packing. Discharge diagnosis and physicochemical characterization demonstrate that the enhancement of O3 synthesis in HD-ZnO relative to HD is mainly ascribed to the strong surface reactions catalyzed by the coating in O2 plasma. The catalytic performance of ZnO coating on O3 generation exhibits a good stability during a 4-h uninterrupted test and can be enhanced by reducing the size of ZnO nano-powder and discharge gap of the reactor. Moreover, the designed HD-ZnO possesses a comparable performance with other superior discharge forms on O3 synthesis.

In this article, the investigation has been carried out for the characterization of the proposed tapered geometry of dielectric barrier discharge (DBD)-based cold atmospheric pressure plasma jet (C-APPJ) on the basis of optical emission spectroscopy (OES) and imaging for different operating parameters, such as argon gas flow rates, applied voltages, and frequencies. The detailed characteristics for the formation of the plasma plume using argon as a working gas have been presented for a wide range of flow rates [1–3 standard liter per minute (SLM)] and frequencies (15–25 kHz). Increasing the pulse frequency, the length and the diameter of the plasma plume increase, while the length of the plasma plume increases when increasing the gas flow rate up to 2 SLM. Time-integrated images have been captured using the intensified charge couple device (ICCD) camera, which illustrates that the plasma plume comprises different emission layers of definite patterns. The propagation dynamics and formation of different emission layers of the plasma plume have also been investigated using the COMSOL Multiphysics simulation. It has been observed that the local electric field of 6 kV/cm is responsible for the propagation of the plasma bullet and the generation of the electron with an average energy of ~9 eV. OES has also been performed to understand the plasma chemistry and identify the reactive species in the C-APPJ. The discharge analysis and characteristics performed through experiment and simulation would certainly be helpful for the design and development of C-APPJ sources.

This review highlighted the current ongoing research in plasma technology and why this process needs to be explored in synergy with the other available/researched technologies worldwide. It provides a broad outlook to study the various elements of non-thermal plasma for CO2 conversion. Most commonly used reactors such as dielectric barrier discharge (DBD) plasma, microwave (MW) plasma, and gliding arc (GA) plasma are described with their operational challenges. It covers the laboratory-scale reactor designs, characterization, the overall efficiencies, the physical and chemical interplay between plasma and catalysis, as well as many of the recent efforts to improve the reaction efficiency. Multiple configurations of plasma reactors along with the effect of operating parameters such as gas flow rate, power input, diluting gas, and others on conversion and energy efficiency are reviewed in this paper. Different catalytic materials and their effect on conversion and energy efficiency are also explored. This review outlines the state-of-the-art development of the plasma catalysis process for CO2 conversion, including CO2 splitting and briefly discussing the mechanistic insights into CO2 hydrogenation and reforming. Additionally, the role and need for the intrinsic rational design of catalyst composition and structure in determining the selectivity of CO2 conversion is also deliberated. A perspective on current bottlenecks and opportunities for the advancement in development of next-generation novel catalysts for plasma catalysis for industrial applications is also presented.

In order to improve the efficiency of dielectric barrier discharge (DBD) contaminants treatment and reduce the treatment cost, a multiphase DBD plasma water treatment reactor is used in this article. When processing methylene blue solution, the electrode distance is 3 mm, the input voltage is 85 V, and the input frequency is 7.8 kHz. The degradation rate can be maintained at about 90% when the experiment is carried out with different concentrations for 10 min. The energy efficiency value of the solution with different concentrations is continuously rising, and the energy efficiency of the solution with a concentration of 150 mg/L reaches 2091 mg/kW $\cdot \text{h}$ . In experiments under different water volume conditions, the degradation rate of the solution with 300 mL water volume was 74% after the same treatment time 30 min, compared with the degradation rate of 100 mL water volume of 89.3%, but the amount of methylene blue in the degraded solution increased. In the experiment of adjusting the gas volume to 100 ml/min, it is found that when the gas volume increases to 100 ml/min, the degradation rate is 86%, which is 20% higher than 67.3% when the gas input is 60 ml/min.

Volatile organic compounds (VOCs) generated in urban workplaces have been considered as significant air pollutants both indoors and outdoors. In order to reduce those harmful VOCs from urban emission sources, a non-thermal plasma reactor equipped with dielectric barrier discharge (DBD) using alternating current (AC) was investigated with a focus on process design including recirculation. Decomposition efficiency of low concentration VOCs was evaluated in terms of energy yield and conversion selectivity. At 20 ppm, the highest decomposition efficiency (97.3 %) was achieved in the treatment of n-hexane, followed by toluene at 96.6 %, MEK at 91.5 % and acetaldehyde at 90.4 %. A recirculation rate (QR) of 50 % improved the system efficiency, particularly for acetaldehyde (49.47 %–63.86 %) and toluene (79.05 %–95.89 %). It also increased the complete energy yield and the selectivity for carbon monoxide (CO) and carbon dioxide (CO2). By-product ozone concentration decreased significantly with increasing recirculation rate at the same input energy level.

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.

Metal-organic frameworks (MOFs) are considered as promising materials for membrane gas separations. Structural defects within a pure MOF membrane can considerably reduce its selectivity and possibly result in a nonselective separation. This work proposes a solution-phase synthesis with dielectric barrier discharge (DBD) plasma to suppress the formation of defects in the pure MOF membrane of CPO-8-BPY. Through comprehensive solid-state characterization with XRD, SEM, XPS, solid-state NMR, and XAFS, DBD plasma is demonstrated to facilitate deprotonation in the H2aip linker, which leads to a smaller and more uniform particle size of CPO-8-BPY. The narrow grain size distribution effectively reduces the pinhole-type defects in the pure CPO-8-BPY membrane and endows it with good ideal selectivity for H2/CH4 (αH2/CH4 = 28.2) and N2/CH4 (αN2/CH4 = 5.4). The selectivity for H2/CH4 of this membrane from a mixed-gas permeation test is found to be 15.4. Molecular simulations are also performed to gain insights into the gas transport properties of this MOF. The results suggest that ligand rotation plays an important role in CPO-8-BPY when being applied to the membrane separation of N2/CH4.

In this work, the dielectric barrier discharge (DBD) humid air plasma was employed for the functionalization of hydrophobic MWCNTs. Effects of different process variables such as voltage, frequency, and processing time of the air-water plasma on the functionalization process were investigated by Fourier transform infrared (FT-IR) analysis. The energy-dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and X-ray diffraction (XRD) were used to characterize functionalized MWCNTs. The stability of the plasma-treated MWCNTs in aqueous solutions was investigated by Ultraviolet-visible (UV-Vis) spectroscopy. At the optimum operating condition, the air-water plasma functionalization technique leads to the highest concentrations of hydrophilic functional groups on the surface structure of the MWCNTs at the frequency of 7 KHz and voltage of 10 kV for 8 minutes. According to the presented results, the dispersion and stability of the MWCNTs in the aqueous solution significantly enhanced by using the proposed eco-friendly humid air plasma functionalization technique.

Non-thermal plasma (NTP) is gaining attention as a powerful tool to induce various reactions. The combination of NTP with catalysts has been successfully used to degrade volatile organic compounds (VOCs) for pollution control. In this study, a series of TiO2-C/5A catalysts, synthesized by carbon dots (C-dots) that decorate TiO2 by sol-gel and wetness impregnation methods, were incorporated with a dielectric barrier discharge (DBD) reactor in a single-stage structure to degrade toluene at atmospheric pressure and room temperature. A proton-transfer reaction mass spectrometer and a CO2 analyzer were used to monitor the concentration variations of organic by-products and CO2 online. The effects of input power, mass ratio of C-dots/TiO2 (TiO2/5A (0 wt%), TiO2-C1/5A (2.5 wt%), TiO2-C2/5A (5 wt%), TiO2-C3/5A (10 wt%)), gas flow rate, initial concentration of toluene on the toluene degradation efficiency, and CO2 selectivity were studied. The plasma-catalyst hybrid system could effectively improve the energy efficiency and reaction selectivity, attaining a maximum toluene degradation efficiency of 99.6% and CO2 selectivity of 83.0% compared to 79.5% and 37.5%, respectively, using the conventional plasma alone. Moreover, the generation of organic by-products also declined dramatically, averaging only half as much in plasma alone. The results also indicated that the appropriate amount of C-dot doping could greatly improve the catalyst efficiency in the hybrid plasma system. This is because the interaction between C-dots and TiO2 favors the formation of photoelectron holes and reduces the energy band gap and the recombination rate of photogenerated electron holes, which facilitates the generation of more active species on the catalyst surface, thereby leading to a more effective degradation reaction. These observations will provide guidance for the interaction studies between NTP and catalysts, not only for the exploration of new chemical mechanisms of aromatic compounds, but also for the screening of favorable materials for the desired reactions.

The oxidation of ozone is very strong, and the products of oxidative decomposition will not cause secondary pollution, so the ozone has become widely used. Dielectric barrier discharge (DBD) is the...

In this study, a comparative decomposition of toluene was investigated using a dielectric barrier discharge (DBD) reactor. The first-time decomposition of the tar model compound was investigated in pure CO gas. The effect of each carrier gas (N2, H2, CO2 and CO), which exists in product gas from the gasifier, was studied on the decomposition of tar analogue (toluene) and product distribution. The specific input energy (SIE) was also varied from 2.5 to 8.5 kJ/L to investigate the optimal removal of tar analogue. The maximum removal of toluene was 89.1% using N2 as carrier gas at 8.5 kJ/L and 1.43 s. However, the minimum removal of toluene was 62.5% using CO carrier gas under the same conditions. The decomposition of toluene in different carrier gases was in the following order: CO

Purpose This paper aims to improve the general circuit of driving and protection based on insulated gate bipolar transistor (IGBT) in dielectric barrier discharge power supply by designing a novel half-bridge inverter circuit with discrete components. Design/methodology/approach With one SG3524 chip, the structure based on discrete components is used to design the IGBT drive circuit. The driving waveform is isolated and sent out by photo-coupler 6N137. The protection circuit is realized by Hall sensor directly detecting the main circuit current, supplemented by a few components, including diodes, resistors, capacitors and triodes. It improves the reliability of the protection circuit. Findings In the driving circuit, the phase difference of signals from two channels are 180°. Moreover, when the duty cycle is set at 40%, it can ensure sufficient pulse width modulation response time. In the protection circuit, when over-current occurs, an intermittent output signal is automatically sent out. Furthermore, the over-current response time can be controlled independently. The peak voltage can be adjusted continuously from 0 to 30 kV with its frequency from 8 to 25 kHz and the power output up to 150 W. Originality/value The novel circuit of driving and protection makes not only its structure simpler and easier to be realized but also key parameters, such as frequency, the duty cycle and the driving voltage, continuously adjustable. Moreover, the power supply is suitable for other discharges such as corona discharge and jet discharge.

In this work, plasma pretreatment of raw cotton fibers combined with silver sorption was used for the preparation of antimicrobial fabrics. Special attention was given to the aging effect investigated seven days after plasma treatment. Raw cotton fabrics were modified with atmospheric pressure dielectric barrier discharge (DBD) in air, nitrogen, and oxygen. After plasma treatment, surface morphology and chemistry were characterized by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively, molecular weight distribution and functional groups profile in cellulose were determined by GPC-MALLS with fluorescence labeling, while sorption properties were evaluated through wettability and moisture sorption measurements. Silver sorption was performed either immediately after treatment or seven days after plasma treatment, in order to investigate the aging effect on the sorption of Ag+. Antimicrobial activity was tested using agar diffusion test against S. aureus, E.coli, and C. albicans. Results have shown that silver sorption is improved and significantly higher when sorption is performed seven days after plasma treatment and consequently antimicrobial activity is also enhanced. This work confirms the significance of plasma aging in natural cellulose fibers' functionalization which presents yet another variable that should be taken into account when planning the procedure for fibers functionalization.

Effects of dielectric barrier discharge plasma have been studied on the wake velocity profiles of a section of a 660 kW wind turbine blade in plunging motion in a wind tunnel. The corresponding unsteady velocity profiles show remarkable improvement when the plasma actuators were operating and the angles of attack of the model were beyond the static stall angles of the airfoil. As a result the drag force was considerably reduced. It is further observed that the plasma-induced flow attenuates the leading edge vortices that are periodically shed into wake and diminishes the large eddies downstream. The favorable effects of the plasma augmentation are shown to occur near the uppermost and lowermost positions of the plunging paths where the wake is primarily dominated by the vortices of the same sign. The wake structure in the presence of the flow induced by the plasma actuators shows that the actual effective angles of attack seen by the plunging airfoil reduces in comparison with that for the case of the plasma augmentation off situation.

Supersaturated solid–solutions in a W–Cr alloy system were fabricated by conventional milling and plasma milling. The different extension mechanisms of the solid solubility that were created by ball milling with and without discharge plasma were studied. The solid–solubility of Cr in W for the P-milling W–Cr alloy system was higher, which indicates that plasma milling promotes the formation of W(Cr) solid–solution more easily than conventional milling. According to Miedema’s model, in the W–Cr alloy system, the free-energy change to form a W(Cr) solid solution by plasma milling is reduced compared with conventional milling because of the heating effect of the discharge plasma. Therefore, a higher stored energy in the grain boundaries and dislocations of the W–Cr nanograins during plasma milling makes it easier to overcome the thermodynamic barrier in the formation of a solid–solution, when compared with conventional milling.

In this paper, the effects of streamwise Nanosecond Dielectric Barrier Discharge (NS-DBD) actuators on Shock Wave/Boundary Layer Interaction (SWBLI) are investigated in a Mach 2.5 supersonic flow. In this regard, the numerical investigation of NS-DBD plasma actuator effects on unsteady supersonic flow passing a 14° shock wave generator is performed using simulation of Navier-Stokes equations for 3D-flow, unsteady, compressible, and k ‐ ω SST turbulent model. In order to evaluate plasma discharge capabilities, the effects of plasma discharge length on the flow behavior are studied by investigating the flow friction factor, the region of separation bubble formation, velocity, and temperature distribution fields in the SWBLI region. The numerical results showed that plasma discharge increased the temperature of the discharge region and boundary layer temperature in the vicinity of flow separation and consequently reduced the Mach number in the plasma discharge region. Plasma excitation to the separation bubbles shifted the separation region to the upstream around 6 mm, increased SWBLI height, and increased the angle of the separation shock wave. Besides, the investigations on the variations of pressure recovery coefficient illustrated that plasma discharge to the separation bubbles had no impressive effect and decreased pressure recovery coefficient. The numerical results showed that although the NS-DBD plasma actuator was not effective in reducing the separation area in SWBLI, they were capable of shifting the separation shock position upstream. This feature can be used to modify the structure of the shock wave in supersonic intakes in off-design conditions.