Search Results (551)

Methane is an abundant carbon resource with significant potential for the sustainable production of hydrogen, syngas, light hydrocarbons, oxygenates, and carbon nanomaterials. However, its efficient utilization remains challenging because of the high stability of the C–H bond, requiring energy-intensive thermocatalytic processes that often suffer from limited selectivity, carbon deposition, and high CO₂ emissions. Plasma-assisted technologies have emerged as a promising alternative by activating methane through energetic electrons and reactive species under non-equilibrium conditions. Although considerable progress has been achieved, existing reviews have primarily focused on individual plasma sources, reaction pathways, or catalyst systems, with limited attention to the coupled interactions among plasma characteristics, radical chemistry, reactor engineering, and product selectivity. This review provides a comprehensive and critical analysis of plasma-assisted methane valorisation by integrating the fundamental mechanisms of electron-impact activation, radical generation, and plasma kinetics with reactor design and process performance. The major plasma reactor technologies, including dielectric barrier discharge, gliding arc, microwave, and plasma jet systems, are critically compared in terms of methane conversion pathways, energy efficiency, operating conditions, reactor configuration, and product distribution. Finally, current challenges and emerging opportunities, including plasma catalysis, advanced reactor architectures, operando diagnostics, and reactor scale-up, are discussed to provide future perspectives for the industrial implementation of plasma-assisted methane valorisation. Full article

Fracturing flowback fluid poses significant pollution risks and potential threats to the surrounding ecological environment, especially soil and groundwater systems. This study innovatively combined the dielectric barrier discharge (DBD) low-temperature plasma technology with the Fenton oxidation process to construct a synergistic degradation system. Systematic investigation of key operational parameters, including discharge voltage, H₂O₂ and Fe²⁺ dosages, and initial pH, was conducted to evaluate their effects on process performance. Under the optimal process parameters, the system achieves over 90% in both COD removal rate and guar gum degradation efficiency, outperforming traditional treatment technologies. Mechanistic analysis suggests that the efficient degradation of HPG may result from the combined action of plasma-generated reactive species and Fenton-derived oxidizing species. However, further identification of transformation products and toxicity evaluation are still required. This research provides a green and efficient new solution for the fracturing flowback fluid treatment, which has significant engineering application value. Full article

To further enhance the application effectiveness and energy efficiency of dielectric barrier discharge plasma coupled with catalytic technology, this study investigates the synergistic effect between coated catalysts and dielectric barrier discharge. A two-dimensional fluid model was established, and numerical simulations were conducted using the finite element method to evaluate NO removal from automobile exhaust gases. Results show that, compared to dielectric barrier discharge alone, the degradation efficiency of low-concentration NO increases by 6%–29% when a coated catalyst is introduced. Three coated catalysts, including Mn/TiO₂/γ-Al₂O₃, Mn/γ-Al₂O₃ and TiO₂, are compared for 1% NO treatment, whose degradation efficiencies are 63.1%, 53.7% and 40.2%, respectively. As the NO concentration increased from 1% to 3%, the degradation efficiency of all three catalysts decreased. In terms of NO₂ by-product generation, the synergistic system with Mn/TiO₂/γ-Al₂O₃ produces the least NO₂. This coupling technology effectively removes low-concentration nitrogen oxides from vehicle exhaust, enriches plasma-catalysis theory, and supports global efforts in controlling motor vehicle emissions pollution. Full article

Plasma-activated water (PAW) is produced through an electrically driven plasma-chemical process. Numerous references confirm that the composition of PAW is sensitive to the parameters such as voltage, gap distance, and temperature. In order to advance the application of PAW, this paper focuses on investigating the impact of temperature on the reactive species in both gaseous and aqueous chemistry in a plasma reactor. A comprehensive model is developed to examine the treatment of deionized water using a dielectric barrier discharge (DBD) plasma reactor, while varying the temperature from 10 °C to 90 °C. The results reveal that as the temperature increases, the concentration of short-lived species in the gas phase, including OH, O, and O₂(¹Δg), increase. Conversely, the concentration of species such as O₃, H₂O₂, N₂O₅, and HO₂NO₂ decrease as a result of decomposition reactions and reactions with the aforementioned short-lived species. Furthermore, the behavior of aqueous chemistry differs from that of the gaseous species, with only N₂O_aq, O_3aq, and ${\mathrm{N}\mathrm{O}}_{3\mathrm{a}\mathrm{q}}^{-}$ achieving high levels of densities. Within the liquid phase, OH_aq emerges as an important species, influencing the densities of H₂O_2aq, NO_2aq, and ${\mathrm{N}\mathrm{O}}_{3\mathrm{a}\mathrm{q}}^{-}$. It is found that high temperatures decrease the pH value of the liquid, subsequently impacting the densities of weak acids and their conjugate ions. These findings contribute to a deeper understanding of PAW preparation, benefiting its development for future applications. Full article

Dielectric barrier discharge (DBD) plasma actuators have attracted increasing attention for anti-icing and de-icing applications due to their ability to combine surface heating and plasma-induced flow control. Their electro-thermal behavior is strongly influenced by exposed electrode material, geometry, and dielectric configuration, often leading to localized hot-spot formation and reduced operational stability. However, the impact of exposed electrode material and electrode thickness remains poorly understood, representing a significant gap in understanding the electrical and thermal response of these devices. This study presents an experimental electro-thermal investigation of DBD plasma actuators employing copper, aluminum, and hybrid copper–aluminum exposed electrodes. Copper and aluminum were selected as exposed materials because they present two contrasting electrical–thermal extremes. The actuators were tested using dielectric barrier thicknesses of 1 mm and 2 mm, considering both standard and enlarged (10 times) exposed electrode thickness. The electrical diagnostics show that aluminum electrodes promote stronger and more uniformly distributed microdischarges due to enhanced discharge initiation, but at the expense of increased power consumption. In contrast, copper electrodes exhibit lower power demand but lead to concentrated current density and localized thermal hot spots. Motivated by this electrical–thermal trade-off, a hybrid electrode was developed to combine the high electrical stability of copper with the discharge uniformity of aluminum. The hybrid configuration demonstrates intermediate power consumption and significantly improved thermal uniformity, effectively mitigating hot spot formation. These results highlight the importance of exposed electrode electrical properties in the electrical and thermal characterization of DBD plasma actuators and identify the hybrid configuration as a promising solution for future thermally driven ice-mitigation applications. Full article

Endogenous matrix metalloproteinases (MMPs) are activated in dentin during carious lesion progression and restorative procedures, degrading the tooth-restoration interface and contributing to restoration failure. This study investigated by means of in situ zymography whether cold atmospheric plasma activation (PA) of distilled water (DW) and phosphate-buffered saline (PBS) modulates endogenous dentinal MMP activity. A Dielectric Barrier Discharge-rod source generated PA liquids, treating DW and PBS for 22 min. Chemical characterization demonstrated that PADW yielded 9.61 mg/L H₂O₂, 18.3 mg/L NO₂⁻, 375.70 mg/L NO₃⁻, and a pH of 3.2. PAPBS yielded 9.79 mg/L H₂O₂, 36.01 mg/L NO₂⁻, 505.74 mg/L NO₃⁻, and a pH of 7.13. Both liquids served as 1 min dentin pretreatments in a simulated restorative procedure using a universal adhesive and resin composite, tested after 24 h. MMP activity was assessed via in situ zymography with fluorescein-conjugated gelatin and confocal microscopy. Data were statistically analyzed (p < 0.05). PADW increased dentinal enzymatic activity, while PAPBS reduced it (p < 0.05). Non-activated PBS elicited higher baseline MMP activity than non-activated DW. The divergent responses likely reflect differences in RONS composition, pH, and initial ionic content between the two liquids. The precise mechanism underlying PA liquid interactions with dentinal MMPs warrants further investigation. Full article

The scientific literature on plasma methods for modifying the surface properties of non-woven polypropylene (NWPP) fabrics is reviewed. The scientific background of the observations reported by different teams is explained, and the technological limits are highlighted. Plasma treatment usually modifies the surface layer, which is beneficial for some applications, such as grafting functional coatings onto the fibers in the surface film of NWPP fabrics. The water contact angle of NWPP fabrics treated by plasmas sustained by the classical dielectric barrier discharges at atmospheric pressure and low-pressure discharges in the range of about 10 to a few 100 Pa rarely drops below 90°, which is explained by the inability to modify fibers deep in the fabrics due to the limited penetration depth of such plasmas. The super-hydrophilic finish can be achieved either by using nanosecond-pulsed atmospheric-pressure discharges or by weakly ionized plasma with a relatively high electron temperature, sustained at a pressure of a few Pa or below. Such plasmas modify the fibers deep in the fabric, which is particularly useful for applications in respiratory masks where the fibers should be coated with ultra-thin films of virucidal substance. The energy efficiency of the latter plasmas is better because practically no gas-phase loss of reactive species occurs, and so is their scalability, making them the most suitable for modifying NWPP fabrics at an industrial scale. While most authors reported only increased wettability with increasing treatment intensity, over-treatment has been reported and is attributed to thermal effects. The range of optimal intensity has yet to be systematically quantified. Full article

This paper reviews numerical modeling approaches for Dielectric Barrier Discharge (DBD) plasma actuators in aircraft active flow control. While extensive experimental studies exist, a dedicated review of computational methodologies—covering macroscopic, microscopic, and empirical models—has been absent. This work systematically evaluates major models (Shyy, Suzen–Huang, Dorr–Kloker, Roth, Orlov–Corke, Massines), discussing their formulations, assumptions, computational cost, and applicability. It synthesizes simulation studies in aerodynamic applications such as separation control, drag reduction, transition delay, film cooling, and compressor stability. Key findings show that macroscopic models offer a practical balance between accuracy and cost for design-oriented studies, whereas microscopic models provide deeper physical insight at higher expense. The review highlights the effectiveness of DBD actuators in modifying boundary layers, delaying stall, and improving aerodynamic efficiency. Finally, persistent challenges are identified—including energy efficiency, scalability, and model calibration and future directions are suggested, such as hybrid modeling, multi-actuator arrays, and real-time control integration. Full article

Dielectric Barrier Discharge (DBD) plasma actuators have shown considerable potential for aerodynamic flow control over fixed wings and helicopter rotors. However, their application to small unmanned aerial vehicle (UAV) propellers operating at high rotational speeds remains largely unexplored. This study experimentally investigates the effectiveness of leading-edge AC-DBD plasma actuators in improving the aerodynamic performance of rotating UAV propellers under hovering conditions. A custom-built experimental test stand was developed to measure thrust, rotational speed, and motor power consumption while supplying high voltage to the rotating blades through high-speed slip rings. A series of 3D-printed propellers with different blade pitch angles was tested at rotational speeds up to 4000 rpm. The results showed negligible performance changes for low-pitch propellers, whereas significant improvements were observed under separated-flow conditions. At nearly constant rotational speed and thrust, plasma actuation reduced the propeller power coefficient by up to 7.66%, resulting in a maximum 9.42% increase in Figure of Merit (FoM). The greatest benefits were obtained for intermediate blade pitch angles, while no measurable improvement was observed under severe separation conditions. These findings demonstrate that plasma actuation is most effective within an intermediate separated-flow regime and highlight its potential as a lightweight active flow-control technology for electrically powered UAVs. Full article

The chemically modified ammonium lignosulfonate (ALS) powders with carboxylic acids such as, oleic (OA) and lactic acid (LA) and γ-butyrolactone (BL) under dielectric barrier plasma discharge (DBD) have been characterized by average molecular weight and particle size determinations, morphology examination by optical and electronic microscopy (SEM), the study of the thermal properties by thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and antioxidant activity tests by DPPH method. The thermal characterization of the modified lignosulfonates reveals their improved thermal stability comparatively with ALS. It has been established that the obtained microparticles are aggregates of particles, covered by modified polymer and exhibit a particular behavior depending on the chemical structure of the used modifier, leading to multifunctional active lignin-based products with better homogeneity. By surface modification, the antioxidant capacity of modified lignosulfonate powders has been maintained. Full article

Plasma-catalytic ammonia synthesis can operate without high temperatures and pressures, and its performance is closely tied to discharge modes. However, research on its microscopic discharge mechanisms remains limited. A 2D fluid model incorporating plasma-activated heterogeneous reactions was developed to investigate voltage polarity effects on discharge dynamics in an N₂/H₂ planar dielectric barrier discharge (DBD) reactor with catalyst-coated barriers. Under both polarities, discharge starts as a gas-phase streamer at the catalyst apex due to local field enhancement and then evolves into a surface ionization wave (SIW) with an order-of-magnitude higher electron density. Positive voltage restricts the SIW to the catalyst surface, whereas negative voltage induces SIWs on both the upper bare dielectric and the catalyst, driven by distinct charge accumulation patterns. During the short discharge pulse, the gas phase primarily functions as a radical generator, while surface reactions dominate NH₃ synthesis. Because positive voltage effectively targets plasma energy to the catalyst surface, it yields a higher peak NH₃ density near the catalyst (2.85 × 10¹⁹ m⁻³) compared to negative polarity (8.10 × 10¹⁸ m⁻³). Full article

This study investigated the effects of repeated dielectric barrier discharge (DBD) plasma applications on the morphological and physiological characteristics of pathogenic Alternaria and Fusarium species. Fungi, including both culture collection strains and environmental isolates, were exposed to sublethal doses of DBD plasma. The results demonstrated that the plasma exposure time required to achieve 90% cell mortality varied significantly among microorganisms, ranging from 2 min and 39 s for Fusarium culmorum DSM 1094 to 5 min and 19 s for Alternaria alternata DSM 62010. Tolerance to oxidative stress, assessed by determining the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of hydrogen peroxide, generally decreased following repeated plasma exposure. Notably, F. tricinctum Ft11S–23 exhibited increased resistance to hydrogen peroxide, with MIC values doubling after fifteen plasma treatments. The MFC also increased significantly, rising from 25.5 mM to 102.0 mM. Furthermore, repeated DBD plasma applications resulted in reduced tolerance of fungi to at least one of the tested fungicides; however, exceptions were observed, including increased tolerance of F. culmorum to specific fungicides. The capacity for biofilm formation was modulated by plasma treatment, with some species exhibiting reduced biofilm formation while others demonstrated increased capacity, depending on the specific pathogen and frequency of plasma exposure. Full article

Modern agriculture faces increasing pressure from rising food demand, resource degradation, and biotic stress factors, highlighting the need for sustainable, non-chemical technologies. Cold atmospheric plasma (CAP) has emerged as a promising non-chemical seed-priming technology with potential applications in sustainable agriculture. The present study investigated the effects of dielectric barrier discharge (DBD)-generated CAP on seed germination and early seedling development in two Solanum lycopersicum genotypes (a common variety and an IdB hybrid) under controlled laboratory conditions. Seeds were exposed to CAP for 1, 2, 3, or 4 min, while untreated seeds served as controls. Early plant performance was evaluated after 47 days by determining germination rate, fresh biomass, dry biomass, and mineral biomass (ash content). CAP exposure duration significantly affected all gravimetric parameters in both genotypes. Among the tested treatments, 1 min exposure consistently produced the highest fresh, dry, and mineral biomass values, whereas longer exposure times (3–4 min) generally reduced seedling growth, indicating the transition from beneficial physiological stimulation to stress-induced inhibition. Despite the more pronounced response observed in the IdB hybrid, the statistical analysis demonstrated that treatment duration, rather than genotype, was the principal factor influencing biomass accumulation. The present results indicate that short-duration CAP treatment represents an effective seed-priming strategy for improving early tomato seedling development. Full article

To address the issues of high switching losses in power devices and device temperature rise caused by hard switching in conventional plasma power supplies, this study presents a dielectric barrier discharge plasma power supply system based on a zero-voltage switching (ZVS) control strategy. First, the design of the plasma power supply input module, the plasma drive control board, the high-frequency transformer, and the dielectric barrier discharge load is presented. Next, a phase-shifted full-bridge topology simulation model based on the ZVS control strategy is developed using PLECS, and the optimal combination of parameters—including duty cycle, phase shift, resonant inductance, and dead time—is discussed. Subsequently, experimental tests are conducted on the dielectric barrier discharge plasma power supply system, with analyses focusing on the soft-switching waveforms of the power devices under the ZVS control strategy and the performance of the dielectric barrier discharge plasma generator load. Experimental results demonstrate that within the proposed system, the plasma exhibits a uniform distribution. Furthermore, junction temperature measurements of the power devices on the circuit board using a temperature tester show that the temperature rise remains within a reasonable range, thereby validating the feasibility of the designed dielectric barrier discharge plasma power supply system. Full article

Carbon dioxide (CO₂) conversion in non-thermal plasma is a promising route for carbon utilisation under mild conditions. This study investigates the performance and dynamic behaviour of kaolin-based catalysts modified with Ni (nickel), Ni–Ce (nickel-cerium), and Fe–Cu (iron-copper) oxides in a Dielectric Barrier Discharge (DBD) reactor. Materials were characterised using X-ray diffraction, energy-dispersive X-ray fluorescence, and scanning electron microscopy with energy-dispersive X-ray spectroscopy. CO₂ conversion was evaluated at varying Plasma Energy Numbers (PEN = 1.65–20) with time-resolved gas analysis over a 10 min period. Results demonstrate that the kaolin support is not inert; its dielectric properties actively influence discharge characteristics. Ni-based catalysts exhibited the highest stable activity, reaching ~53% conversion for samples calcined at 500 °C. Conversely, adding cerium oxide significantly decreased conversion and induced temporal instabilities, contrasting with its typical role in thermal catalysis. Time-resolved measurements revealed that Ni–Ce and Fe–Cu systems exhibit initial activity followed by gradual deactivation, suggesting plasma-induced surface restructuring. These findings highlight that catalyst performance in DBD is governed by a complex interplay of chemical activity and plasma–material interactions. The generated time-series data provide a robust foundation for machine learning applications in predictive modelling and stability classification of plasma-catalytic systems. Full article