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Oyster mushroom cultivation can be hindered by slow budding and low yield. This study explored the potential of atmospheric pressure gliding arc discharge plasma to address these challenges. Two types (direct and indirect) of plasma treatment methods were applied to the mushroom spawn and straw, and plasma-activated water in the growth environment in oyster mushrooms. Physicochemical characterization of plasma-activated water revealed increased conductivity, oxidation-reduction potential, nitrate/nitrite levels, and hydrogen peroxide with longer treatment times, and decreased pH of water. Plasma-treated spawn exhibited faster budding and earlier colonization compared to others. The longest stem was observed in spawn exposed to plasma. Mushrooms produced with a spawn treatment, straw, and plasma-activated water spray have positively influenced production and biological efficiency. Therefore, compared to the control spawn, the production of mushroom spawn treated with plasma increased nearly 1.5 times. Overall, plasma treatment enhanced mushroom development and yield, indicating its positive impact on oyster growth. [ABSTRACT FROM AUTHOR]

In this work, gliding arc discharge (GAD) was used to produce air plasma and investigate the influence of the discharge parameters on the composition of the air plasma, vibrational temperatures, and the production of NOx. It was demonstrated that the main particles obtained in the GAD air plasma were N2*, N2+, N+, NOγ, and O. It was observed that the reduction in the discharge frequency increased the intensity of the excited nitrogen molecules lines and reduced the nitric oxide (NO) and nitrogen dioxide (NO2) gas concentrations. The increase in the output voltage prolonged the duration of arc discharge and enhanced the intensities of the emission lines of the N2+, O, and NOγ species and the concentrations of NO and NO2 gasses. It was shown that the increase in the air flow rate from 6.7 L/min to 15.6 L/min decreased the concentration of the produced NO gas by 24%. Additionally, the line intensities of all main species in air plasma were enhanced. Studies have shown that the NO and NO2 gas concentrations (selectivity of NO and NO2) can be controlled by varying the air flow, output voltage, and discharge frequency. The highest NOx concentration of 2380 ppm was produced at 250 V, when the direct air flow was 11.2 L/min. [ABSTRACT FROM AUTHOR]

Plasma-activated water can efficiently inactivate pathogenic microorganisms and is considered to be a potent disinfectant in the medical, food, and agricultural industries. In this study, the air discharged by the gliding arc was mixed with different gases including O2, ambient air, synthetic air, and N2 at different flow rates to produce the activated gases, which were then activated gases were inducted into saline to prepare plasma-activated saline (PAS). The gaseous reactive species in the activated gases were composed of NO, NO2, and N2O5 and the aqueous reactive species in the PAS included H2O2, NO2−, NO3–, ⋅ OH , and 1O2 with different intensities, while the inactivation effects of the PAS also varied with the type and the flow rates of the mixed gases in the activated gases. The inactivation effects of the PAS treated by the discharged air mixed with O2, ambient air, and synthetic air started to become weak after 3 h placement. Scavenger analysis demonstrated that the 1O2 played a critical role in the inactivation process. This study indicated that air discharged by the gliding arc mixed with different gases could regulate the reactive species and the biological effects of PAS, providing insight into the preparation of PAS applied for disinfection. [ABSTRACT FROM AUTHOR]

Plasma seed pretreatment is an important means to rapidly improve seed quality. The studies on plasma-generating devices suitable for continuous seed pretreatment at atmospheric pressure have been relatively limited. Gliding arc discharge can generate atmospheric pressure plasma at room temperature, which provides a new way to use plasma to treat seeds at ambient temperature and pressure. By analyzing the influence of structural characteristics, such as gliding arc electrode shape, discharge distance, and electrode opening angle on plasma distribution, a plasma seed treatment method based on negative pressure guidance was proposed, and the electrode structure was optimized. The results show that the reasonable matching of electrode structure parameters can improve the gliding arc guiding ability of the discharge electrode. Comparing the three electrode shapes, it was found that the triangular electrode had the best gliding arc guiding ability, and it had the potential to further increase the plasma size with the increase in the electrode size. The discharge distance and electrode opening angle had a significant impact on the gliding arc guiding ability of the discharge electrode. When the discharge distance was 15 mm and the electrode opening angle was 76°, the structure parameters of the plasma seed treatment electrode were matched with each other, and the best processing capacity was achieved. After 10 s of gliding arc plasma treatment with the optimized triangular electrode structure, the seed germination rate and germination index of Leymus chinensis ((Trin.) Tzvel) increased by 33.3% and 13.8%. This study provides a theoretical basis for the design and optimization of gliding arc electrode structures and serves as a reference for the research and development of plasma generators for continuous seed treatment at atmospheric pressure. [ABSTRACT FROM AUTHOR]

In this work, gliding arc discharge (GAD) was used to produce air plasma and investigate the influence of the discharge parameters on the composition of the air plasma, vibrational temperatures, and the production of NOx. It was demonstrated that the main particles obtained in the GAD air plasma were N2*, N2+, N+, NOγ, and O. It was observed that the reduction in the discharge frequency increased the intensity of the excited nitrogen molecules lines and reduced the nitric oxide (NO) and nitrogen dioxide (NO2) gas concentrations. The increase in the output voltage prolonged the duration of arc discharge and enhanced the intensities of the emission lines of the N2+, O, and NOγ species and the concentrations of NO and NO2 gasses. It was shown that the increase in the air flow rate from 6.7 L/min to 15.6 L/min decreased the concentration of the produced NO gas by 24%. Additionally, the line intensities of all main species in air plasma were enhanced. Studies have shown that the NO and NO2 gas concentrations (selectivity of NO and NO2) can be controlled by varying the air flow, output voltage, and discharge frequency. The highest NOx concentration of 2380 ppm was produced at 250 V, when the direct air flow was 11.2 L/min.

In this paper, the Magnetically Stabilized Gliding Arc Discharge (MSGAD) system was constructed to produce non-thermal plasma using argon gas under atmospheric pressure. A gliding plasma discharge was stabilized by a magnetic field for the purpose of a planned investigation. The emission spectra of the generated plasma using a gliding arc discharge system were recorded under atmospheric pressure, with a constant value of alternating voltage (4 kV) and at different gas flow rates of) 0.5–2.5 (L/min. The plasma parameters, including electron temperature (Te), electron density (ne), plasma frequency, Debye length and electron temperature, were calculated. The electron temperature was measured using the Boltzmann plot method, and the electron density was determined using the Stark broadening method. The results show an increase of the electron temperature from 1.138 to 1.277eV and electron density from 2.78×1017 to 3.48×1017 cm-3 as the gas flow increased from 0.5 to 2.5 L/min. Also, the spectral line intensity increases with the increase of the gas flow rate. [ABSTRACT FROM AUTHOR]

This research investigates the catalytic performance of Ni/Al2O3 in the methanation of CO2 under both thermal and Gliding Arc Discharge (GAD) conditions. Utilizing in situ transmission infrared (TIR) absorption spectroscopy and quadrupole mass spectrometry (QMS), the study analyzes the transient behavior of the plasma-catalyst interaction of CO2 methanation. GAD significantly enhances CO2 conversion and methane production compared to thermal catalysis by CO2 activation, facilitating the rapid transformation of intermediate species on the catalyst surface. Additionally, the study provides a detailed analysis of the electrical characteristics of GAD, capturing voltage and current waveforms that illustrate the transient arc behavior under different phases of the discharge process. The results indicate that lower pressures, while reducing overall CO2 conversion, enhance methane production by suppressing the gas phase CO2 conversion to CO and promoting surface reactions. This comprehensive study not only advances the understanding of plasma-assisted catalysis for CO2 methanation but also highlights the potential of this technology for enhancing greenhouse gas utilization with renewable energy-driven plasma, paving the way for future optimization and industrial application. [ABSTRACT FROM AUTHOR]

A gliding arc discharge (GAD) plasma device has been developed and tested. Possible applications areas for GAD plasma could be microalgae suspension treatments and the creation of plasma-activated water. To understand its behavior, the influence of the input power on the electrical characteristics of the generated GAD plasma was investigated using an oscilloscope. The waveforms of the voltage and current of GAD plasma are presented. The duration of the discharge time and the evolution of the arc during discharge were determined and investigated. It was revealed that the increase in the output voltage prolonged the duration of the arc discharge. The composition of the air plasma was investigated using a flame-emission spectrometer and acousto-optic emission spectrometer. It was revealed that the main species in the emission spectra of the GAD air plasma were N2, N2+, N+, NO, and O species. Furthermore, the increase in the input power enhanced the ionization degree of the air plasma and increased the intensities of the emission lines associated with N2+, NO, and O species. An increase in the conductivity of the BG-11 medium was observed. Physicochemical analyses of the plasma-activated BG-11 medium indicated an increase in the concentration of nitrite and nitrate ions and hydrogen peroxide with an enhancement of the voltage. [ABSTRACT FROM AUTHOR]

A gliding arc discharge (GAD) plasma reactor was developed for partial oxidative reforming (POR) H 2 production. Air was used as carrier gas and oxidant. The effects of the molar ratio of oxygen to carbon(O/C), input power and residence time on POR reaction were investigated. Under O/C ratio 0.75, input power 35 W and residence time 35 s, the energy yield of H 2 was 68.7 L/kWh and the main products were H 2 and CO. The GAD plasma was diagnosed with OES. A zero-dimensional(0-D) reaction kinetic model of was established. The simulation results were consistent with the experimental ones. The mechanism of C 12 H 26 conversion, the generation and consumption of products were discussed in detail. The experiment results were in good agreement with the simulated ones. The primary path of n -dodecane conversion was the direct cracking reaction and H 2 mainly derived from the recombination reaction between H atom and CH 4 , C 3 H 6 and C 2 H 6. [Display omitted] • A GAD reactor was used for POR of n -dodecane for hydrogen production. • A 0-D kinetic model was developed to explore the mechanism. • The results of OES were used to analyze the generation and consumption of substances. • The direct cracking reaction contributes the most to the n -dodecane conversion. [ABSTRACT FROM AUTHOR]

Plasma assisted combustion has been proposed as an efficient technique to enhance combustion, especially under the extreme conditions. For shedding light on the interactions between plasma and turbulent flame at extended conditions, a burner design with integrated electrodes was used to couple a non-thermal gliding arc (GA) discharge to a turbulent flame. The morphology and dynamic behaviors of the GA assisted flame under extended flow rates and gas temperatures were investigated by high-speed video imaging. It is found that two distinct types of flame (named as Flame A and Flame B) can be sustained by the GA discharge depending on the local flow conditions. Flame A was sustained by the GA on stable anchor points, while Flame B moved together with the thin plasma volume of the gliding arc, behaving as an unstable flame. When the fed air gas temperature was increased, Flame A became more stable while Flame B became fragile and extinguished easily. Furthermore, the phenomenological findings under different flow conditions imply typical four flame types for the GA discharge assisted combustion system, including the self-sustained flame at relatively low Reynolds number (Re), the GA sustained stable flame at moderate Re number, the GA sustained unstable flame and the GA assisted auto-ignited and propagating flame at relatively large Re number. In all, the GA discharge seems to provide various effects on combustion depending on the overall turbulence as well as the local equivalence ratio, the gas temperature, etc. [ABSTRACT FROM AUTHOR]

In this paper, the direct effects of gliding arc discharge (GAD), dielectric barrier discharge (DBD), and argon plasma jet (APJ) discharge as generators of reactive oxygen and nitrogen species (RONS) on wheat seed yield have been evaluated. This evaluation was studied for a period of eight month in fall planting. The plasma-activated water was used for irrigation during this period. Physical quantities of the plant, such as length, weight as well as panicle length, neck diameter, weight, number of seeds per panicle, and grain weight were measured and appropriate comparisons were made on the measurements. The results indicated that cold atmospheric pressure plasma increased plant length and biomass. Moreover, the length and diameter of the panicle was also increased which caused the in relative increase in number and weight of seeds. Therefore, it can be claimed that cold plasma has a positive effect on the growth and reproduction of wheat.

Plasma seed pretreatment is an important means to rapidly improve seed quality. The studies on plasma-generating devices suitable for continuous seed pretreatment at atmospheric pressure have been relatively limited. Gliding arc discharge can generate atmospheric pressure plasma at room temperature, which provides a new way to use plasma to treat seeds at ambient temperature and pressure. By analyzing the influence of structural characteristics, such as gliding arc electrode shape, discharge distance, and electrode opening angle on plasma distribution, a plasma seed treatment method based on negative pressure guidance was proposed, and the electrode structure was optimized. The results show that the reasonable matching of electrode structure parameters can improve the gliding arc guiding ability of the discharge electrode. Comparing the three electrode shapes, it was found that the triangular electrode had the best gliding arc guiding ability, and it had the potential to further increase the plasma size with the increase in the electrode size. The discharge distance and electrode opening angle had a significant impact on the gliding arc guiding ability of the discharge electrode. When the discharge distance was 15 mm and the electrode opening angle was 76°, the structure parameters of the plasma seed treatment electrode were matched with each other, and the best processing capacity was achieved. After 10 s of gliding arc plasma treatment with the optimized triangular electrode structure, the seed germination rate and germination index of Leymus chinensis ((Trin.) Tzvel) increased by 33.3% and 13.8%. This study provides a theoretical basis for the design and optimization of gliding arc electrode structures and serves as a reference for the research and development of plasma generators for continuous seed treatment at atmospheric pressure.

The effects of plasma-activated water (PAW), generated through atmospheric pressure air gliding arc discharge, on the germination and growth parameters of cauliflower (Brassica oleracea, variety Botrytis) seeds have been investigated. Results demonstrate significant influences of PAW on seed germination characteristics and seedling growth parameters. Increasing the exposure time of seeds to plasma from 0 to 20 min leads to a notable increment in the water uptake rate, ranging from approximately 94.0% to 115.0%. Furthermore, the physio-chemical characteristics of PAW are examined, revealing its transformation into acidic solutions, accompanied by rising electrical conductivity, oxidation-reduction potential, total dissolved solids, and nitrate and nitrite concentrations with longer treatment times. Notably, applying PAW for 10–15 min results in higher seed germination and seedling growth. Comparative experiments involving PAW and control water demonstrate enhanced germination, increased root and shoot lengths, and elevated chlorophyll content. However, prolonged exposure to PAW shows adverse effects. Cauliflower plants treated with 10 min and 15 min of PAW exhibit the highest chlorophyll concentration, root and shoot lengths. These findings underscore the potential of PAW to improve seed germination and plant growth, emphasizing the importance of adjusting the plasma treatment period for each specific seed. [ABSTRACT FROM AUTHOR]

Plasma-assisted combustion (PAC) has shown excellent performance in the ignition and combustion enhancement of scramjet combustors. A multi-channel gliding arc (MCGA) plasma placed on the sidewall surface of a scramjet combustor was employed to enhance combustion near the flame blowout limit (BL) in a C 2 H 4 -fueled and cavity-based model scramjet combustor. Wall static pressure measurements, simultaneous 10 kHz CH* chemiluminescence imaging from the top and side views, optical emission spectroscopy, and discharge waveform measurements were used to elucidate the combustion physics throughout the PAC events. For the current cavity configuration and fueling condition, a general estimate of the flame BL in a rich-fuel environment was provided, in which a fuel flow rate (FFR) was 7.5 g/s. Once the FFR was exceeded, the flame was unstable and blown out, whereas the MCGA plasma demonstrated an excellent flame stabilization ability. The flame BL of the scramjet combustor in the presence of the MCGA plasma has an increase of ∼29%. Two PAC processes, including enhancement mode and re-ignition mode, were distinguished to play a vital role in extending the flame BL. The two PAC processes showed that the spark-type discharge generated by the MCGA could ignite the local fuel-rich mixture and increase the flame BL. The local ignition is dominated by the continuous accumulation of the massive flame kernels with the local fuel-rich mixture, as well as more heat and species exchanges. [ABSTRACT FROM AUTHOR]

In recent years, a large number of countries have connected and distributed photovoltaics in remote rural areas, aiming to promote the use of clean energy in rural areas. The solar energy that is not used in time needs to be discarded, resulting in a large amount of wasted energy. Rural areas are closely related to agricultural production, and solar energy can be used for agricultural nitrogen fixation to supplement the nitrogen needed by crops and effectively use the upcoming waste of solar energy. A photovoltaic-driven plasma reactor for nitrogen fixation in agriculture was designed in this study. The air inlet and outlet holes are arranged above and below the reactor to facilitate air entry and directly interact with the gliding arc generated at the bottom of the electrode to achieve atmospheric nitrogen fixation in agriculture. The characteristics of gliding arc development in the process of nitrogen fixation in agriculture were studied experimentally. There are two discharge modes of the gliding arc discharge: one is steady arc gliding mode (A-G Mode), and the other is breakdown gliding mode (B-G Mode). By collecting discharge signals, different discharge modes of gliding arc discharge were analyzed, and the effect of the air flow rate on the discharge period and discharge mode ratio distribution is discussed. The effects of the air flow rate on the yield, specific energy input, and energy consumption in plasma agriculture were studied. The experimental results show that with an increase in the air flow rate, the B-G mode takes up a larger proportion and the gliding arc discharge period is shortened. However, the higher the proportion of the B-G mode, the more unfavorable the production of nitrogen oxides. Although the nitrogen oxides generated by the system are not particularly excellent compared with the Haber-Bosch ammonia process (H-B process), the access to distributed photovoltaic roofs in rural and remote areas can effectively use available resources like water, air, and solar, and avoid energy waste in areas where wind and solar are abandoned. [ABSTRACT FROM AUTHOR]

Tetracyclines (TCs) are often discussed as one of the emerging contaminants detected in water matrices and studied for their persistence towards conventional water treatment technologies. In this work, the treatment of TC in aqueous solutions with nonthermal plasma gliding arc process was investigated. The degradation efficiency of TC was studied along with the effect of initial concentration, working gas, pH, and the presence of a radical scavenger. The generation of reactive oxidative species was characterized by the quantification of radical hydroxyl, hydrogen peroxide, ozone, nitrite, and nitrate. Mineralization efficiency was examined by assessment of Total organic carbon evolution. Experimental results have shown that the gliding arc plasma is effective for the treatment of TC. At an initial concentration of 5 mg/L: degradation rates of 94.95% and 60.45% were achieved, while mineralization rates were 81.3% and 57.34% under O2 and air plasma, respectively. O2 plasma exhibited an immense potential for the generation of reactive oxygen species. Meanwhile, air plasma showed better degradation performance in the presence of a radical scavenger. Moreover, degradation products were identified by mass spectroscopy analysis and degradation pathway was proposed. The gliding arc process proposed in this work is promising for the removal of TC antibiotics. HIGHLIGHTS First work to ever investigate the removal of tetracycline by a nonthermal plasma gliding arc process.; Effect of plasma gas, initial concentration, pH and radical scavenger was studied.; O2 plasma was most effective in radical hydroxyl generation and in tetracycline degradation while air plasma showed better results in presence of radical scavenger.; Degradation products were identified and a pathway was suggested.;

Mitigating climate change requires the development of technologies that combine energy and transport sectors. One of them is the production of sustainable fuels from electricity and carbon dioxide (CO2) via power-to-liquid (PtL) plants. As one option for splitting CO2, plasma-based processes promise a high potential due to their flexibility, scalability, and theoretically high efficiencies. This work includes a modeling and techno-economic analysis. A crucial element is the process of the joint project PlasmaFuel, in which two plasma technologies are included in a PtL plant to produce synthetically sulfur-free marine diesel. The results are divided into three scenarios, which differ in the use of different boundary conditions and thus represent different degrees of technology development. The evaluation results in process efficiencies from 16.5% for scenario 2018/20 to 27.5% for scenario 2050, and net production costs between EUR 8.5/L and EUR 3.5/L. Furthermore, the techno-economic potential is mapped in order to open up development steps in the direction of costs below EUR 2.0/L. The present work allows statements regarding system integration and the industrial use of the plasma-based process.; moreover, conclusions can be drawn towards the most important levers in terms of process optimization. [ABSTRACT FROM AUTHOR]

A gliding arc discharge (GAD) plasma device has been developed and tested. Possible applications areas for GAD plasma could be microalgae suspension treatments and the creation of plasma-activated water. To understand its behavior, the influence of the input power on the electrical characteristics of the generated GAD plasma was investigated using an oscilloscope. The waveforms of the voltage and current of GAD plasma are presented. The duration of the discharge time and the evolution of the arc during discharge were determined and investigated. It was revealed that the increase in the output voltage prolonged the duration of the arc discharge. The composition of the air plasma was investigated using a flame-emission spectrometer and acousto-optic emission spectrometer. It was revealed that the main species in the emission spectra of the GAD air plasma were N2, N2+, N+, NO, and O species. Furthermore, the increase in the input power enhanced the ionization degree of the air plasma and increased the intensities of the emission lines associated with N2+, NO, and O species. An increase in the conductivity of the BG-11 medium was observed. Physicochemical analyses of the plasma-activated BG-11 medium indicated an increase in the concentration of nitrite and nitrate ions and hydrogen peroxide with an enhancement of the voltage.

Gasification of biomass is an industrial process utilized to produce product gas that can be used in electrical power generation with internal combustion engines. However, there remain huge challenges with regards to tar and other pollutants, thus their removal before further use is necessary. Non-thermal plasma method can be considered as a novel and efficient way for treatment of tar from product gas. In this work, a laboratory-scale, reverse vortex flow gliding arc plasma reactor was developed and tested for the removal of tar model compound using naphthalene as surrogate. Effects of total gas feed rate in the range of 20–60 L/min, applied voltage in the range of 50–220 V, hence, power input in the range of 300–460 W with initial naphthalene concentration of 610 ± 50 mg/m3 on removal and energy input were investigated. It was found the tar removal efficiency increased with increasing applied voltage. Maximum naphthalene removal efficiency of 85% was achieved at applied high voltage of 15 kV and specific energy input of 0.13 kWh/m3 with energy utilization efficiency of about 4.60 g/kWh. From the findings, non-thermal plasma technology appeared to offer great potential in the removal of biomass tar from gasification. The technology may be promising for possible application to real biomass tar cracking and upgrading of product gas from gasification.

A multi-channel gliding arc (MCGA) plasma with an average power of 6000 W is utilized to control the flame flashback in a dual-mode scramjet combustor with a cavity flameholder. Optical measurements, including synchronous high-speed CH* emissions and high-speed schlieren, simultaneous high-speed camera with the oblique view and high-speed CH* emission, accompanied by the three-dimensional RANS simulation, were employed to characterize the flame flashback with or without the MCGA plasma. The results show that a typical flame flashback cycle can be observed with a period of ∼2 ms in the combustor. The back pressure reduced by the dynamic heat release of the reaction zone is not sufficient to form the steady thermal choking in the mainstream in the absence of the MCGA, which results in the oblique shocks and bow shocks appearing in dual-mode scramjet combustion. When the plasma is added, the flame is strengthened near the plasma region, and the combustion oscillation is suppressed significantly. The re-ignition and attachment characteristics of the MCGA plasma provide the new flame kernels to the mainstream flame, and the leading edge of the mainstream flame follows the MCGA plasma. Due to the relatively stable heat release near the fuel jet assisted by the plasma, the thermal choking is stable presented in the combustor with bow shocks by higher back pressure, indicating that the combustion oscillation is suppressed by the MCGA plasma in the dual-mode scramjet combustor.

Gliding arc is a promising plasma technology for water activation due to its high energy efficiency for producing reactive nitrogen species (RNS), which is believed as the key agent for the sustained bactericidal effect of plasma-activated water (PAW). Nitric oxide (NO) is the major product of gliding arc and also widely exists in PAW, but the production mechanism of aqueous NO and its role in sterilization have been little investigated before. In this paper, NO-rich plasma effluent gas is produced by gliding arc discharge and introduced into water to produce PAW. The concentrations of gaseous and aqueous reactive species are detected, which decrease with the increasing air flowrate of the gliding arc. To clarify the contribution of plasma-induced RNS on water activation, the NO + air mixed gas is used to simulate the plasma effluent gas, and the results show that the two gases have similar gaseous composition and aqueous NO yield. Compared with the NO + Ar mixed gas with the same NO proportion, the NO + air mixed gas produces much more aqueous NO, implying that the presence of O2 significantly enhances the production of aqueous NO. The sterilization experiments demonstrate the key role of aqueous NO in sterilization, but an acidic environment is necessary for aqueous NO to achieve a potent bactericidal effect. [ABSTRACT FROM AUTHOR]

Gliding arc is a promising plasma technology for water activation due to its high energy efficiency for producing reactive nitrogen species (RNS), which is believed as the key agent for the sustained bactericidal effect of plasma-activated water (PAW). Nitric oxide (NO) is the major product of gliding arc and also widely exists in PAW, but the production mechanism of aqueous NO and its role in sterilization have been little investigated before. In this paper, NO-rich plasma effluent gas is produced by gliding arc discharge and introduced into water to produce PAW. The concentrations of gaseous and aqueous reactive species are detected, which decrease with the increasing air flowrate of the gliding arc. To clarify the contribution of plasma-induced RNS on water activation, the NO + air mixed gas is used to simulate the plasma effluent gas, and the results show that the two gases have similar gaseous composition and aqueous NO yield. Compared with the NO + Ar mixed gas with the same NO proportion, the NO + air mixed gas produces much more aqueous NO, implying that the presence of O2 significantly enhances the production of aqueous NO. The sterilization experiments demonstrate the key role of aqueous NO in sterilization, but an acidic environment is necessary for aqueous NO to achieve a potent bactericidal effect. [ABSTRACT FROM AUTHOR]

In this study, different plasma-activated liquids were evaluated for their antimicrobial effects against Escherichia coli, as well as for their cytotoxicity on mammalian cells. The PALs were prepared from distilled (DIS), deionized (DI), filtered (FIL), and tap (TAP) water. Additionally, 0.9% NaCl saline solution (SAL) was plasma-activated. These PALs were prepared using 5 L/min air gliding arc plasma jet for up to 60.0 min of exposure. Subsequently, the physicochemical properties, such as, the oxidation-reduction potential (ORP), the pH, the conductivity, and the total dissolved solids (TDS) were characterized by a water multiparameter. The PALs obtained showed a drastic decrease in the pH with increasing plasma exposure time, in contrast, the conductivity and TDS increased. In a general trend, the UV-vis analyses identified a higher production of the following reactive species of nitrogen and oxygen (RONS), HNO2, H2O2, NO3−, and NO2−. Except for the plasma-activated filtered water (PAW-FIL), where there was a change in the position of NO2− and NO3− at some pHs, The higher production of HNO2 and H2O2-reactive species was observed at a low pH. Finally, the standardized suspensions of Escherichia coli were exposed to PAL for up to 60.0 min. The plasma-activated deionized water (PAW-DI pH 2.5), plasma-activated distilled water (PAW-DIS pH 2.5 and 3), and plasma-activated tap water (PAW-TAP 3.5) showed the best antimicrobial effects at exposure times of 3.0, 10.0, and 30.0 min, respectively. The MTT analysis demonstrated low toxicity of all of the PAL samples. Our results indicate that the plasma activation of different liquids using the gliding arc system can generate specific physicochemical conditions that produce excellent antibacterial effects for E. coli with a safe application, thus bringing future contributions to creating new antimicrobial protocols. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two magnetically assisted GAD reactors were developed for biomass tar reforming. • MAGAD generates a larger discharge region and more reactive species. • Magnetic field in MAGAD creates a synergy between Lorenz force and gas thrust. • MAGAD exhibits superior reforming performance compared to MSGAD and NGAD. • MAGAD promotes C 2 H 2 formation while suppressing liquid by-products. Gliding arc discharge (GAD) holds significant potential for energy and environmental applications, particularly in biomass tar reforming. In this study, we developed two GAD reactors coupled with a magnetic field for biomass tar reforming. The reactors were designed with two different configurations by varying the magnetic field direction relative to the electrodes: magnetically accelerated gliding arc discharge (MAGAD) and magnetically stabilized gliding arc discharge (MSGAD). The reforming performance and discharge characteristics of these two configurations were systematically evaluated and compared with those of a normal GAD (NGAD). MAGAD demonstrated superior reforming performance, achieving the highest conversion for toluene (71.4 %) and phenol (87.5 %), as well as the highest yields of H 2 (22.4 %) and C 2 H 2 (12.6 %) at a magnetic field intensity of 133 mT. In contrast, MSGAD achieved the highest energy yield (47.1 g/kWh) but exhibited lower tar conversion due to reduced discharge power. In the MAGAD system, the magnetic field generates a synergistic effect between the Lorenz force and gas thrust, accelerating and elongating the arc along the electrodes. This results in increased discharge power and frequency, as well as an expanded discharge region. This leads to the generation of more reactive species, which enhances the breakdown of benzene rings into short-chain hydrocarbons and reduces the formation of liquid byproducts. These findings demonstrate the potential of manipulating magnetic fields to optimize GAD systems for efficient biomass tar reforming, offering a promising strategy to improve the performance of plasma-based chemical reactions. [ABSTRACT FROM AUTHOR]

Non-thermal plasma can be generated by gliding arc discharge units and is used in various applications including disinfection of the surface, inactivation of fungi, viruses, and bacteria. Degradation of the electrodes through prolonged use is common. It is caused by bombardment by plasma-charged particles causing changes to the structure and chemistry of its electrodes which in turn leads to a reduction in the efficiency of the plasma. In this study, the discharged plasma from a gliding arc unit was investigated using optical emission spectrometry (OES). Also studied were the electrodes of the unit after prolonged use. The structure and metallographic properties of the electrodes were evaluated using positron annihilation lifetime spectroscopy (PALS), X-ray diffraction analysis (XRD) and scanning electron microscopy—energy dispersive X-ray spectroscopy (SEM-EDX) and compared to data from new unused samples. The size of defects and holes were also compared using PALS. It was found that the intensity of species decreased significantly with prolonged use of the unit as the copper electrodes degraded. It was also found that the internal structure, as well as the surface of the used electrodes, had changed significantly compared to the unused samples, the radius of holes in the electrode material had decreased and the intensity of holes increased. Furthermore, the planes of the atomic structure of the copper electrode have moved closer. The approach developed in this study has been shown an effective non-destructive method for routine evaluation of the electrodes and maybe a development further for monitoring and quality assurance programs for maintaining high plasma efficiency as well as for research into improvements to electrode material design. [ABSTRACT FROM AUTHOR]

As a wiring material for printed electronics (PE), copper is strongly needed instead of silver. For a sintering method of copper traces, we have developed the method using oxygen pump and atmospheric pressure plasma, and demonstrated the ink composed of nanoparticles can be sintered to bulk-like structure. In this study, we have improved the sintering system to make it effective especially for copper inks made of submicron particles. We have tried to increase the thickness of the sintered layer and decrease the resistivity by changing the power supply system of plasma discharge and increasing the plasma density. The improved system has successfully demonstrated that a copper trace at least 4 μ m thick can be sintered and that the resistivity decreases to approximately 3.3 μ Ω·cm. These results can lead to huge breakthroughs in PE based on copper. [ABSTRACT FROM AUTHOR]

In order to improve the combustion performance of a ramjet under low temperature and pressure, a gliding arc plasma actuator was designed based on a typical evaporation flameholder. The discharge characteristics, as well as the activating effect of single-channel and three-channel gliding arc plasma under different carrier gas flow rates, were studied. Results show that with the increase in the carrier gas flow rate, the average duration of the gliding arc discharge becomes shorter, while the average power increases, and the specific input energy decreases. Compared with single-channel discharge, three-channel discharge has higher discharge power and energy injection rate, which makes a bigger actuated space. Through gliding arc plasma, the kerosene is cracked and H2, CH4, C2H2, C2H4, C3H6 and other small molecule components are produced. For three-channel gliding arc discharge, the effective cracking rate and the production rate of each component are higher than those of the single-channel discharge; both of them gradually increase with the increase in the carrier gas flow rate. The experiment results indicate that three-channel gliding arc plasma can effectively widen the ignition boundary and improve the combustion efficiency of ramjet combustion. The ignition pressure boundary is expanded from 60 kPa to 50 kPa under 390 K; the combustion efficiency is increased from 76% to 82%. [ABSTRACT FROM AUTHOR]

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This study compares the effects of nonthermal plasma treatment on quinine water solutions for two configurations—the corona‐like discharge and the gliding arc discharge (GAD). Different electrolytes were added to the quinine solutions to modify the initial pH and enhance electrical conductivity for plasma discharge ignition directly in the liquid. A slightly higher quinine decomposition rate of 2.9 μg W−1 after 5 min of the treatment was achieved by GAD. From measured spectra, it was found that the absorption maximum at 332 nm was split into two separated peaks in the acidic and basic solution. The study of the time stability of quinine solutions has revealed quinine instability and that postpreparation time has influenced the plasma treatment effect. [ABSTRACT FROM AUTHOR]

Mitigating climate change requires the development of technologies that combine energy and transport sectors. One of them is the production of sustainable fuels from electricity and carbon dioxide (CO2) via power-to-liquid (PtL) plants. As one option for splitting CO2, plasma-based processes promise a high potential due to their flexibility, scalability, and theoretically high efficiencies. This work includes a modeling and techno-economic analysis. A crucial element is the process of the joint project PlasmaFuel, in which two plasma technologies are included in a PtL plant to produce synthetically sulfur-free marine diesel. The results are divided into three scenarios, which differ in the use of different boundary conditions and thus represent different degrees of technology development. The evaluation results in process efficiencies from 16.5% for scenario 2018/20 to 27.5% for scenario 2050, and net production costs between EUR 8.5/L and EUR 3.5/L. Furthermore, the techno-economic potential is mapped in order to open up development steps in the direction of costs below EUR 2.0/L. The present work allows statements regarding system integration and the industrial use of the plasma-based process.; moreover, conclusions can be drawn towards the most important levers in terms of process optimization.

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plasma reforming is a promising technology to transform tars from biomass gasification into valuable fuels and chemicals. However, the key performance (tar conversion, gas yield and energy efficiency) of the plasma tar reforming process can be significantly influenced by operating conditions such as the gas composition. In this study, the effect of CO 2 , steam and O 2 on the plasma reforming of toluene, a model tar compound, was investigated in a gliding arc (GA) reactor. Compared to the plasma reforming of toluene with N 2 , the presence of oxidative gases (CO 2 , H 2 O and O 2) can generate a highly reactive plasma environment, thus creating new reaction pathways in the plasma conversion of toluene. The optimal content of CO 2 , H 2 O and O 2 to balance the toluene conversion, syngas yield and energy efficiency in the plasma reforming was 2 vol%, 4 vol% and 2 vol%, respectively, suggesting that the presence of an appropriate amount of oxidative gas (CO 2 , H 2 O and O 2) is important to maximize the key performance of the plasma reforming process. The highest toluene conversion of 78.3%, syngas yield of 73.9% and energy efficiency of 69.5 g/kWh were achieved simultaneously in the plasma reforming of toluene containing 4 vol% steam. The reaction pathways in the plasma reforming of toluene have been proposed through the analysis of gas and liquid products coupled with optical emission spectroscopic diagnostics. [Display omitted] • Gliding arc plasma reforming of toluene as a tar model compound was performed. • The content of different oxidative gases on the plasma reforming of toluene was investigated. • The optimal content of CO 2 , H 2 O and O 2 was found to maximize the plasma reforming performance. • The highest toluene conversion of 78.3% and energy efficiency of 69.5 g/kWh were achieved. [ABSTRACT FROM AUTHOR]

The behavior of a gliding arc discharge in a supersonic flow is investigated. The discharge is generated in a device which combined electrodes in a 2-D convergent–divergent (i.e., Laval) nozzle. Experimental observations with a high-speed camera, as well as measurements of the mass flow rate and local pressure, suggest that a gliding arc discharge was successfully generated in the supersonic flow. The arc displacement velocity fluctuated due to the existence of shock waves, and the ignition position of the discharge shifted further away from the throat as the reservoir pressure increased. Numerical calculations of the fluid dynamics in the nozzle qualitatively describe the experimental observations. The observed and modeled shift of the ignition position can be explained as the product of the pressure and the electrode distance being minimized at the position just before the first shock wave is produced, and where the breakdown occurs. [ABSTRACT FROM AUTHOR]

Characteristics of a repetitive nanosecond pulsed gliding arc discharge in an air flow at atmospheric pressure driven by a SiC MOSFET inverter power supply are reported for the first time. The gliding arc discharge is produced using two diverging electrodes. The repetition frequency of the pulsed voltage is set from 10 to 300 kHz, and the pulse duration is 500 ns. The propagation distance of the gliding arc discharge almost linearly increases with increasing the repetition frequency of the applied pulsed voltage, resulting in an increase in the discharge reaction area. Dynamics of ignitions and propagation of the gliding arc discharge are revealed with a high-speed camera imaging synchronized with the applied pulsed voltage. The result shows that a shortcut discharge with a different generation mechanism appears. It is found that formation of a shortcut current path between the two legs of the stretched arc discharge occurs, resulting in a new ignited arc discharge. Thus, the pulsed gliding arc discharge can be repeatedly generated without a reignition at the shortest gap between the electrodes. The probability of the occurrence of the shortcut discharge increases as the repetition frequency of the pulsed voltage increases. Additionally, measurements of optical emission spectra of the gliding arc discharge show the presence of excited N2, OH, and NH radicals. The OH emission dominates in the gliding arc discharge with the shortcut events. It can be concluded that the repetition frequency of the applied pulsed voltage becomes the control knob for chemical reactions in future industrial applications. [ABSTRACT FROM AUTHOR]

Non-thermal plasma is a promising technology for high purity nanomaterial synthesis in a fast, flexible and controllable process. Gliding arc discharge, as one of the most efficient non-thermal plasmas, has been widely used in gas treatment but rarely studied for the nanomaterial synthesis. In this study, a comparison study for carbon nanosheets synthesis including toluene dissociation and graphite exfoliation was investigated in a 2D gliding arc reactor at atmospheric pressure. The effects of gas flow rate, precursor concentration and power input on the structures of carbon nanosheets produced through the two synthesis routes were explored and compared. Amorphous carbon nanosheets were produced in both approaches with a few crystalline structures formation in the case of toluene dissociation. The thickness of carbon nanosheets synthesized from graphite exfoliation was less than 3 nm, which was thinner and more uniform than that from toluene dissociation. The flow rate of carrier gas has direct influence on the morphology of carbon nanomaterials in the case of toluene dissociation. Carbon spheres were also produced along with nanosheets when the flow rate decreased from 2 to 0.5 L/min. However, in the case of graphite exfoliation, only carbon nanosheets were observed regardless of the change in flow rate of the carrier gas. The generated chemical species and plasma gas temperatures were measured and estimated for the mechanism study, respectively. [ABSTRACT FROM AUTHOR]

Hydrogen production from partial oxidation reforming of methane in a gliding arc discharge (GAD) reactor is investigated. The effects of input power, the oxygen‐carbon molar ratio (O/C), and residence time are studied, respectively. Products such as H2, CO, CO2, and C2‐C4 hydrocarbons can be detected in the outlet gas. The experimental result shows that the input power of 36.4 W, the relitively low O/C of 0.705 and the 13.8 s residence time in this system will bring the highest H2 energy yield. Compared to the decomposition of methane, partial oxidation of methane with air can maintain a stable discharge state and no carbon deposition on electrodes is observed during the reaction process. Optical emission spectroscopy (OES) is also employed to characterize this methane‐air plasma. Based on the results of the experiment and OES, a possible mechanism of methane partial oxidation process was proposed, which points out that collisions of high‐energy electrons and excited N2 species (mainly N2(A)) with other species (such as O2, CH4) in the plasma region are two main ways for the activation of this reforming system. Hydrogen is generated principally through the H‐abstraction reaction and the H‐coupling reaction. [ABSTRACT FROM AUTHOR]

n-dodecane steam reforming (SR) process was investigated from both experimental and modelling views in gliding arc plasma. The effects of water-carbon molar ratio, n-dodecane concentration, input power and residence time on the conversion, yield, energy efficiency EE(C 12 H 26) and hydrogen energy yield EY(H 2) were revealed. The most dominant spectral lines detected by optical emission spectroscopy (OES) are CN violet and H α (3d2D-2p2p0). The highest yields of H 2 and CO are 50.1% and 49.9%, respectively. A zero-dimension reaction kinetic model containing 105 species and 793 reactions was developed for the SR process. Using CHENKIN-PRO, the presumable reaction pathways of n-dodecane, H 2 , CO, H 2 O and CO 2 were described in detail. H 2 and CO were produced mainly through reaction C 2 H 4 + H ⇌ C 2 H 3 + H 2 and reaction HCCO + H ⇌ C H 2 (S) + CO. [Display omitted] • Experimental and modelling study of n-dodecane steam reforming in a GAD plasma reactor. • A 0-D model was found to describe the main pathways of reaction processes. • The highest yields of H 2 and CO are 50.1% and 49.9%, respectively. • Reaction pathways of n-dodecane, H 2 , CO, H 2 O and CO 2 were described in detail. [ABSTRACT FROM AUTHOR]

• A novel magnetically enhanced gliding arc (MEGAD) is developed for CO 2 activation. • The arc motion behavior is optimized with the presence of a magnetic field. • The plasma volume is significantly enlarged for chemical reactions in the MEGAD. • The addition of magnet improves the CO 2 conversion by 40.6% at flow rate = 1 L/min. In this work, a novel magnetically enhanced gliding arc discharge (MEGAD) reactor was developed and investigated for the activation of carbon dioxide to produce value-added carbon monoxide. The effect of the external magnetic field on the gliding arc motion behavior, electrical characteristics and CO 2 decomposition has been systematically investigated under different flow rates. Results indicate that the presence of the external magnetic field can remarkably enlarge the plasma region, due to the facilitating effect of Lorentz force, especially at a low flow rate. The gliding arc motions with and without a magnetic field at low flow rates show different patterns: a short-circuiting pattern of a "motionless" gliding arc without a magnetic field and a regular 'ignition – elongation – extinguishment' pattern of a motional gliding arc with a magnetic field. Interestingly, the MEGAD exhibits higher CO 2 conversion in comparison to traditional gliding arc systems (up to 40.6% higher at flow rate = 1 L/min), especially at relatively low flow rates. The optimal CO 2 dissociation performance achieved is: 12.2% CO 2 conversion and 24.3% energy efficiency at 3000 mL/min or 11.2% CO 2 conversion and 27.9% energy efficiency at 4000 mL/min, with the presence of magnetic field. [ABSTRACT FROM AUTHOR]

A gliding arc discharge (GAD) with a water spray system was constructed. A non-thermal plasma, generated between two V shaped electrodes in an ambient argon driven by 100 Hz AC voltage, was investigated using optical emission spectroscopy (OES) with different gas flow rates (0.5, 1, 1.5, 2, 2.5, 3 1/min). Boltzmann plot method was used to calculate electron temperature (Te) and electron density (ne). The electrodes design was spectrally recognized and its Te value was about 0.588-0.863 eV, while the ne value of 6.875×1017-10.938×1017 cm-3. The results of the plasma diagnostics generated by gliding arc showed that increasing gas flow rates was associated with decreased electron temperature (Te), Debye length, and Debye Number, along with decreased electron density (ne) and plasma frequency. [ABSTRACT FROM AUTHOR]

Abstract A burner design with integrated electrodes was used to couple a gliding arc (GA) discharge to a high-power and large-scale turbulent flame for flame stabilization. Simultaneous OH and CH 2 O planar laser-induced fluorescence (PLIF) and CH PLIF measurements were conducted to visualize instantaneous structures of the GA-assisted flame. Six different regions of the GA-assisted flame were resolved by the multi-species PLIF measurements, including the plasma core, the discharge-induced OH region, the post-flame OH region, the flame front, the preheat CH 2 O region and the fresh gas mixture. Specifically, the OH profile was observed to be ring-shaped around the gliding arc discharge channel. The formaldehyde (CH 2 O) was found to be widely distributed in the entire measurement volume even at a low equivalence ratio of 0.4, which suggest that long-lived species from the gliding arc discharge have induced low-temperature oxidations of CH 4. The CH layer coincides with the interface of the OH and CH 2 O regions and indicates that the flame front and the discharge channel are spatially separated by a distance of 3–5 mm. These results reveal that the discharge column acts as a movable pilot flame, providing active radicals and thermal energy to sustain the flame. High-speed video photography was also employed to record the dynamics of the GA-assisted flame. This temporally resolved data was used to study the ignition and propagation behaviors of the flame in response to a temporally modulated burst-mode discharge. The results indicate that turbulent flame can be sustained by matching temporal parameters of the high-voltage bursts to the extinction time of flame. [ABSTRACT FROM AUTHOR]

Abstract The effects of non-thermal plasma (NTP) using a gliding arc (GA) discharge was studied with harvested Nam Dok Mai mangoes to determine the rate of retardation of anthracnose disease (Colletotrichum gloeosporioides). Different fluxes of argon (Ar) gas (3–5 L/min) and treatment times (5–7 min) with NTP delayed mycelium growth as well as decreasing fungal spore survival and anthracnose severity. A GA discharge at 5 L/min Ar for 7 min had a significantly higher (p ≤ 0.05) inhibition of C. gloeosporioides mold growth on potato dextrose agar and mango fruit at 30 °C together with reducing the number of fungi spores in suspension. Hydroxyl radicals (OH●) together with hydrogen peroxide (H 2 O 2) may be responsible for the suppression of the postharvest anthracnose disease with mangoes. Highlights • Gliding arc discharge non-thermal plasma (NTP) was applied in Nam Dok Mai mangoes. • Different fluxes of argon gas and treatment times were investigated. • Anthracnose severity and mycelium growth were delayed and decreased by NTP. • OH.● and H 2 O 2 are responsible for suppression of anthracnose disease in mangoes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Plasma reforming of mixed toluene and naphthalene as tar surrogate is carried out. • The role of H 2 O and CO 2 in the plasma reforming of tar has been investigated. • The formation of gaseous/liquid products and reactive species has been analyzed. • Upgrading of producer gas and tar removal can be achieved simultaneously. • Oxidative species formed in the plasma contributes to the enhanced tar conversion. Abstract Steam reforming of mixed toluene and naphthalene as tar surrogate has been investigated in an AC gliding arc discharge plasma, with particular emphasis on better understanding the effect of steam and CO 2 on the reaction performance. Results show that H 2 , C 2 H 2 and CO are the major gas products in the plasma steam reforming of tar for energy recovery. The addition of a small amount of steam remarkably enhances the conversions of both toluene and naphthalene, from 60.4% to 76.1% and 57.6% to 67.4%, respectively, as OH radicals formed by water dissociation create more reaction pathways for the conversion of toluene, naphthalene and their fragments. However, introducing CO 2 to this process has a negative effect on the tar reforming. Optical emission spectroscopic diagnostics has shown the formation of a variety of reactive species in the plasma process. Trace amounts of monocyclic and bicyclic aromatic condensable by-products are also detected. The destruction of toluene and naphthalene can be initiated through the collisions of tar surrogates with energetic electrons, N 2 excited species, OH and O radicals etc. Further optimization of the plasma tar destruction is still needed because the complexity of the tar component in a practical gasifier could decrease the tar conversions. [ABSTRACT FROM AUTHOR]