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Background: Silver nanoparticles are extensively researched for their antimicrobial properties. Cold atmospheric plasma, containing reactive oxygen and nitrogen species, is increasingly used for disinfecting microbes, wound healing, and cancer treatment. Therefore, this study examined the effect of water activated by dielectric barrier discharge (DBD) plasma and gliding arc discharge plasma on the antimicrobial activity of silver nanoparticles from Alborzia kermanshahica. Methods: Silver nanoparticles were synthesized using the boiling method, as well as biomass from Alborzia kermanshahica extract grown in water activated by DBD and GA plasma. The physicochemical properties of the synthesized nanoparticles were evaluated using UV-vis spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), zeta potential analysis, transmission electron microscopy (TEM), and gas chromatography-mass spectrometry (GC-MS) analysis. Additionally, the disk diffusion method was used to assess the antimicrobial efficacy of the manufactured nanoparticles against both Gram-positive and Gram-negative bacteria. Results: The spectroscopy results verified the presence of silver nanoparticles, indicating their biosynthesis. The highest amount of absorption (1.049) belonged to the nanoparticles synthesized by boiling under GA plasma conditions. Comparing the FTIR spectra of the plasma-treated samples with DBD and GA revealed that the DBD-treated samples had more intense peaks, indicating that the DBD method proved to be more effective in enhancing the functional groups on the silver nanoparticles. The DLS results revealed that the boiling method synthesized silver nanoparticles under DBD plasma treatment had a smaller particle size (149.89 nm) with a PDI of 0.251 compared to the GA method, and the DBD method produced nanoparticles with a higher zeta potential (27.7 mV) than the GA method, indicating greater stability of the biosynthesized nanoparticles. Moreover, the highest antimicrobial properties against E. coli (14.333 ± 0.47 mm) were found in the DBD-treated nanoparticles. TEM tests confirmed that spherical nanoparticles attacked the E. coli bacterial membrane, causing cell membrane destruction and cell death. The GC-MS results showed that compounds like 2-methylfuran, 3-methylbutanal, 2-methylbutanal, 3-hydroxy-2-butanone, benzaldehyde, 2-phenylethanol, and 3-octen-2-ol were much higher in the samples that were treated with DBD compared to the samples that were treated with GA plasma. Conclusion: The research indicated that DBD plasma was more efficient than GA plasma in boosting the antimicrobial characteristics of nanoparticles. These results might be a cornerstone for future advancements in utilizing cold plasma to create nanoparticles with enhanced antimicrobial properties. [ABSTRACT FROM AUTHOR]

A novel plasma reactor is being investigated for green NOx production, crucial for nitrate‐based fertilizer manufacturing. Various parameters, including air flow rates, gas ratios, ozone, and catalyst effects are explored for NO → NO2 conversion. NOx concentrations reach ~0.6 vol%, with a total production of ~9.7 gr/h and energy cost of ~3.0 mJ/mol, notably favorable for atmospheric gliding arc plasma. Selectivity (~75%) towards NO2 is achieved with ozone addition or catalytic treatment, pivotal for nitrate fertilizer and HNO3 production. [ABSTRACT FROM AUTHOR]

Per-and Polyfluoroalkyl substances (PFASs) are recalcitrant organofluorine contaminants, which demand urgent attention due to their bioaccumulation potential and associated health risks. While numerous current treatments technologies, including certain plasma-based treatments, can degrade PFASs, their complete destruction or mineralization is seldom achieved. Extensive aqueous PFAS mineralization capability coupled with industrial-level scaling potential makes gliding arc plasma (GAP) discharges an interesting and promising technology in PFAS mitigation. In this study, the effects of GAP discharge’s thermal and reactive properties on aqueous perfluorooctanesulfonic acid (PFOS) mineralization were investigated. Treatments were conducted with air and nitrogen GAP discharges at different plasma gas temperatures to investigate the effects of plasma thermal environment on PFOS mineralization; the results show that treatments with increased plasma gas temperatures lead to increased PFOS mineralization, and discharges in air were able to mineralize PFOS at relatively lower plasma gas temperatures compared to discharges in nitrogen. Studies were conducted to identify if GAP-based PFOS mineralization is a pure thermal process or if plasma reactive chemistry also affects PFOS mineralization. This was done by comparing the effects of thermal environments with and without plasma species (air discharge and air heated to plasma gas temperatures) on PFOS mineralization; the results show that while GAP discharge was able to mineralize PFOS, equivalent temperature air without plasma did not lead to PFOS mineralization. Finally, mineralization during treatments with GAP discharges in argon and air at similar gas temperatures were compared to investigate the role of plasma species in PFOS mineralization. The results demonstrate that treatments with argon (monoatomic gas with higher ionization) lead to increased PFOS mineralization compared to treatments with air (molecular gas with lower ionization), showing the participation of reactive species in PFOS mineralization.

A combination of a gliding arc plasmatron (GAP) reactor and a newly designed tubular catalyst bed (N-bed) was applied to investigate the post-plasma catalytic (PPC) effect for dry reforming of methane (DRM). As comparison, a traditional plasma catalyst bed (T-bed) was also utilized. The post-plasma catalytic effect of a Ni-based mixed oxide (Ni/MO) catalyst with a thermal catalytic performance of 77% CO2 and 86% CH4 conversion at 700 ℃ was studied. Although applying the T-bed had little effect on plasma based CO2 and CH4 conversion, an increase in selectivity to H2 was obtained with a maximum value of 89% at a distance of 2 cm. However, even when only α-Al2O3 packing material was used in the N-bed configuration, compared to the plasma alone and the T-bed, an increase of the CO2 and CH4 conversion from 53% and 53% to 69% and 69% to 83% was achieved. Addition of the Ni/MO catalyst further enhanced the DRM reaction, resulting in conversions of 79% for CO2 and 91% for CH4. Hence, although no insulation nor external heating was applied to the N-bed post plasma, it provides a slightly better conversion than the thermal catalytic performance with the same catalyst, while being fully electrically driven. In addition, an enhanced CO selectivity to 96% was obtained and the energy cost was reduced from ∼ 6 kJ/L (plasma alone) to 4.3 kJ/L. To our knowledge, it is the first time that a post-plasma catalytic system achieves this excellent catalytic performance for DRM without extra external heating or insulation.

In this study, effectiveness of the optimal gliding arc (OGA) plasma on Pacific white shrimp (PWS) immersed in 3% Laurus nobilis leaf essential oil (EO) was evaluated in three types of packaging, including atmosphere, vacuum, and modified atmosphere packaging (MAP). Laurus nobilis leaf EO contains high quantities of 1,8-cineole and α-terpinyl acetate with no significant effects on the bacterial load compared to OGA plasma. OGA plasma was used to compensate for the low antimicrobial effects of L. nobilis leaf EO. Considering parameters pH, PV, TVBN, and melanosis, the shrimps were acceptable for consumption at duration of 10 days. [ABSTRACT FROM AUTHOR]

With the increasing role of hydrogen in the global market, new ways of hydrogen production are being sought and investigated. One of the possible solutions might be the plasma pyrolysis of methane. This approach provides not only the desired hydrogen, but also valuable carbon-containing products, e.g., carbon black of C2 compounds. This review gathers information from the last 20 years on different reactors that were investigated in the context of methane pyrolysis, emphasizing the different products that can be obtained through this process. [ABSTRACT FROM AUTHOR]

Traditional industrial nitrogen fixation (NF) process uses the Haber-Bosch process which requires high temperature and high pressure, causing high energy consumption and serious pollution. Gliding arc plasma (GAP) combines the advantages of thermal plasma and cold plasma, which can efficiently produce active species and improve energy efficiency obviously. It has great application potential in the field of NF, and has received extensive attention in recent years. However, the research on NF via GAP is relatively fragmented at present. It is necessary to summarize the specific content. The research progress of NF via GAP at home and abroad in past 10 years is reviewed in this paper, mainly including GAP discharge mechanism, reactor design, process parameters and NF reaction mechanism. GAP discharge has B-G mode with breakdown following gliding discharge and A-G mode with continuous steady discharge. A-G mode discharge helps to improve nitrogen fixation efficiency. With the continuous development of GAP discharge technology, the electrode structure in GAP reactor has evolved from the traditional 2D blade structure to a variety of 3D cylindrical structures. Based on process optimization, GAP facilitates the vibrational excitation of N2 molecules, thereby promoting the splitting and transformation of N2 molecules. In the last, the research on NF through GAP is prospected. [ABSTRACT FROM AUTHOR]

Hydrogen is an energy carrier with a very high energy density (>119 MJ/kg). Pure hydrogen is barely available; thus, it requires extraction from its compounds. Steam reforming and water electrolysis are commercially viable technologies for hydrogen production from water, alcohols, methane, and other hydrocarbons; however, both processes are energy-intensive. Current study aims at understanding the methane and ethanol-water mixture pathway to generate hydrogen molecules. The various intermediate species (like CH X , CH 2 O, CH 3 CHO) are generated before decomposing methane/ethanol into hydrogen radicals, which later combine to form hydrogen molecules. The study further discusses the various operating parameters involved in plasma reforming reactors. All the reactors work on the same principle, generating plasma to excite electrons for collision. The dielectric barrier discharge reactor can be operated with or without a catalyst; however, feed flow rate and discharge power are the most influencing parameters. In a pulsed plasma reactor, feed flow rate, electrode velocity, and gap are the main factors that can raise methane conversion (40–60%). While the gliding arc plasma reactor can generate up to 50% hydrogen yield at optimized values of oxygen/carbon ratio and residence time, the hydrogen yield in the microwave plasma reactor is affected by flow rate and feed concentration. Therefore, all the reactors have the potential to generate hydrogen at lower energy demand. • Hydrogen production via the methane reforming pathway is discussed. • Ethanol decomposes into intermediate species that further splits into •H radical • Various plasma reforming reactors for H 2 production are discussed. • Influencing parameters in plasma reforming are identified. • Various process parameters affecting H 2 production are reviewed. [ABSTRACT FROM AUTHOR]

Hydrogen production via plasma methane pyrolysis is investigated using a microwave plasma torch (MPT) and a gliding arc plasmatron (GAP). The performance of the two plasma sources in terms of methane conversion, product spectrum, and energy efficiency is compared. The physical and chemical properties of the produced carbon particles are compared. The methane conversion is higher in the GAP than in the MPT. In the MPT amorphous spherical carbon particles are produced in the volume of the plasma source. In the GAP methane pyrolysis in the volume stops after the production of acetylene. The conversion of acetylene into solid carbon takes place in a heterogeneous reaction on top of the electrode surfaces instead. This leads to a lower hydrogen selectivity, higher acetylene selectivity and more platelet‐like morphology of the produced carbon particles when compared to the MPT. [ABSTRACT FROM AUTHOR]

Wheat, a strategic global agricultural product, is prone to contamination by hazardous fungi and toxins, with aflatoxin being particularly prevalent and perilous. This study aimed to evaluate the efficacy of cold plasma in deactivating Aspergillus flavus (A. f.) and Aspergillus parasiticus (A. p.), as well as aflatoxins in wheat grains, offering an alternative to conventional chemical and thermal treatments. Wheat grains inoculated with fungi were subjected to humid air cold plasma at four power levels (5.39, 6.88, 8.98, and 10.88 W) and three plasma exposure periods (2, 6, and 12 min). Post-plasma treatment, Aflatoxin concentrations were analyzed using HPLC, while modified Gompertz and Baranyi and Roberts' mathematical models were employed to study the growth kinetics of A. f. and A. p. species. Findings revealed that samples treated with 10.88 W power for 12 min exhibited a substantial reduction of 64%, 41%, 59%, 40%, and 61% in B1, B2, G1, G2 aflatoxins, and total aflatoxin, respectively. Additionally, plasma led to a 78.74% and 68.57% reduction in the growth of A. f. and A. p. fungi, respectively. Notably, plasma induced a fungal inhibitory effect by prolonging the lag time and decreasing the growth rate. These results underscore the significant potential of cold plasma as a capable technique for fungal inactivation and the emerging disinfection of contaminated wheat grains. • Gliding Arc cold plasma technology reduces wheat aflatoxin content. • Cold plasma affects growth of Aspergillus flavus and Aspergillus parasiticus. • Cold plasma extends wheat shelf-life by slowing microorganism growth. [ABSTRACT FROM AUTHOR]

With the increasing role of hydrogen in the global market, new ways of hydrogen production are being sought and investigated. One of the possible solutions might be the plasma pyrolysis of methane. This approach provides not only the desired hydrogen, but also valuable carbon-containing products, e.g., carbon black of C2 compounds. This review gathers information from the last 20 years on different reactors that were investigated in the context of methane pyrolysis, emphasizing the different products that can be obtained through this process.

The hyperburner is a key component of a TBCC engine, and its reliable ignition and stable operation are critical. The gliding arc plasma igniter driven by differential pressure has the technical advantages of low energy consumption and high jet temperature. In this paper, the electrical and flow characteristics of the gliding arc plasma igniter are studied, and the basic ignition experiment in the hyperburner is carried out. Electrical characteristic experiments show that the discharge duration, the evolution of the gliding arc and the fracture frequency are affected by the pressure difference between the inlet and outlet of the igniter (Δp). With the increase in Δp, the frequency of the trapezoidal envelope in the voltage and current waveforms increases, and the frequency of the evolution and fracture of the gliding arc increases. The continuous discharge time of the gliding arc decreases when Δp = 550 Torr. The flow characteristic experiments show that the velocity of the swirl sheath is increased and the protective effect on the gliding arc is enhanced with the increase in Δp. In the range of 20–550 Torr, the jet length first increases and then decreases with the increase in Δp. The jet length reaches a maximum of 31 mm at Δp = 50 Torr. Basic ignition experiments show that proper Δp can widen the lean ignition limit and shorten the ignition delay time. In the working conditions of this paper, the ignition effect is the best when Δp = 350 Torr, which can widen the lean ignition limit by 37.5% and shorten the ignition delay time by 17%. After increasing the oil–gas ratios, the combustion is more complete and the ignition delay time can be shortened by 93.1% at most. [ABSTRACT FROM AUTHOR]

Kaolin samples obtained from Cameroon were used to produce geopolymer binders. Prior to its application, the raw kaolin samples were activated through the gliding arc plasma treatment using both spatial post-discharge and direct mode. A mixture of sodium hydroxide and silicate was used as the alkaline solution. In order to study the influence of the modifications generated by the gliding arc plasma treatment on the geopolymerization process, X-ray diffraction, thermogravimetric analysis, differential scanning calorimeter and Fourier transform infrared spectroscopy were carried out. In addition, scanning electron microscopy, nitrogen physisorption and compression tests analysis were also carried out on the resulting geopolymer samples to access their mechanical performance. The results showed that the geopolymerization process was not completed at the curing temperature of 90 °C. Plasma spatial post-discharge mode treated kaolin led to 20.48% increase in compressive strength when compared with the geopolymer prepared from raw kaolin. [ABSTRACT FROM AUTHOR]

In spite of being both a one-step solution to several problems associated with woodworking and also energy efficient, the application of microwave (MW) modification in wood research has remained very limited and this promising method has practically no use in wood industries across the globe. Research done so far in this field primarily sheds light on its potential in enhancing wood permeability, treatability and uniform wood drying. While MW treatments are mostly used on wet or green wood, another modification technique, plasma, has potential benefits to synergistically enhance the effects of MW treatment, but so far has not been applied on wet or green wood specimens. This study takes a first step to investigate the effects of plasma treatments (PT) on green wood specimens, as well as combinations of MW and plasma treatments. As a preliminary study, the methodology focuses on water contact angle measurements, since these are most commonly used as indicators for surface modifications in industrial applications. An exponential time dependence was found for the contact angle on the investigated samples of Norway spruce (Picea abies Karst.). Initial contact angles after droplet deposition increased due to drying and migration of organic molecules during treatments. In comparison with the literature, the effect of plasma was significantly less pronounced on wet wood specimens. The initial contact angles showed the lowest statistical variations after MW treatment, whereas plasma increased inhomogeneities. The final contact angles on treated specimens was lowest for PT-only specimens as well as specimens treated with plasma after MW. In contrast to the initial contact angles, the final contact angles showed the lowest variations after PT. Wetting rates were insignificantly improved by plasma, with reduced statistical variations after all treatments.

A gliding arc plasma has the advantages of strong reactivity, high energy density, and easy scale-up, so it is very competitive in the field of plasma-based N 2 fixation. In this work, we designed an underwater transfer arc discharge plasma N 2 fixation system based on a reverse vortex flow gliding arc. In full contact with air and water, the plasma could realize the efficient conversion of N 2 , O 2 , and H 2 O, obtaining gaseous NO, NO 2 , and activated water rich in NO x *. The experiment showed that an underwater transfer arc discharge was formed when the current was greater than 0.6 A. Under this operating condition, the conversion rate of N 2 reached 1.63%, the concentration of NO x reached 2.4%, and the production rate of nitrogen-containing products was about 3.41 mol/h. In addition, the energy consumption was as low as 2.21 MJ/mol, the lowest reported value for atmospheric-pressure rotary gliding arc plasma-based N 2 fixation. The generated activated water had abundant NO 3 − and NO 2 − ions, which could be directly applied as N 2 fertilizer in agriculture, promoting plant germination and growth. This paper describes an environmentally friendly and efficient technical route toward developing industrial N 2 fixation/green agriculture, strongly supporting the carbon neutrality concept. • A reverse vortex flow gliding arc under water was developed for N 2 fixation. • The transfer or non-transfer arc can discharge stably in air or under water. • The N 2 fixation energy consumption was reduced to 2.21 MJ/mol. • The plasma-activated water was rapid produced while N 2 fixation. [ABSTRACT FROM AUTHOR]

• The water-rich methanol spray combustion can be sustained by gliding arc discharge. • The tolerance of water content in methanol is extended to 60 % for spray combustion. • The required energy for arc generation is less than that for dehydration of methanol. • Combustion efficiency is enhanced in the operation range. To achieve the goal of net zero by 2050, carbon dioxide emissions must be reduced using carbon–neutral fuels, and methanol is a feasible choice for gas turbines, IC engines, and furnaces. Methanol can be prepared by bio-process or thermal catalytic processes, but the crude product contains much water. Crude methanol must be dehydrated into high-grade methanol to enable its use as fuel. The dehydration process is the most energy-intensive step in methanol production. Therefore, this study investigated the feasibility of adding different proportions of water to methanol as a fuel for plasma-assisted spray combustion by using low-power gliding arc plasma. Based on the current sprayer setup, using plasma to sustain water-content methanol is more energy-efficient than refining it. The results delineate that plasma can sustain the combustion of methanol in a spray, even when the methanol contains 60 % water. The length and lift-off height of the flame are related to the water content of the fuel. To illustrate this distinguishing phenomenon, this study used CH and OH fluorescence to conduct a more in-depth analysis. The distribution of CH* radicals indicated that the gliding arc plasma enhanced the flame heat release rate, which may be why the flammability limit extended to greater proportions of water with methanol. It's fascinating to observe that blended fuel with higher water content can result in higher OH chemiluminescence signals. This suggests that the dissociation of water vapor, caused by the thermal effect of the gliding arc, plays a crucial role at the flame base locations. In addition, the flammability limits, emissions, and combustion efficiency of methanol/water spray combustion with and without plasma assistance were all examined. [ABSTRACT FROM AUTHOR]

A combination of a gliding arc plasmatron (GAP) reactor and a newly designed tubular catalyst bed (N-bed) was applied to investigate the post-plasma catalytic (PPC) effect for dry reforming of methane (DRM). As comparison, a traditional plasma catalyst bed (T-bed) was also utilized. The post-plasma catalytic effect of a Ni-based mixed oxide (Ni/MO) catalyst with a thermal catalytic performance of 77% CO 2 and 86% CH 4 conversion at 700 ℃ was studied. Although applying the T-bed had little effect on plasma based CO 2 and CH 4 conversion, an increase in selectivity to H 2 was obtained with a maximum value of 89% at a distance of 2 cm. However, even when only α-Al 2 O 3 packing material was used in the N-bed configuration, compared to the plasma alone and the T-bed, an increase of the CO 2 and CH 4 conversion from 53% and 53% to 69% and 69% to 83% was achieved. Addition of the Ni/MO catalyst further enhanced the DRM reaction, resulting in conversions of 79% for CO 2 and 91% for CH 4. Hence, although no insulation nor external heating was applied to the N-bed post plasma, it provides a slightly better conversion than the thermal catalytic performance with the same catalyst, while being fully electrically driven. In addition, an enhanced CO selectivity to 96% was obtained and the energy cost was reduced from ∼ 6 kJ/L (plasma alone) to 4.3 kJ/L. To our knowledge, it is the first time that a post-plasma catalytic system achieves this excellent catalytic performance for DRM without extra external heating or insulation. [Display omitted] • A new post-plasma catalyst bed improves plasma catalysis for DRM. • High CO 2 and CH 4 conversion of 79% and 91% was obtained. • The energy cost decreased from ∼ 6 kJ/L to 4.3 kJ/L with the new bed. • Efficient heat and mass transport was achieved without extra heating or insulation. [ABSTRACT FROM AUTHOR]

A low-cost reverse flow plasma system powered by argon gas pumping was built using homemade materials in this paper. The length of the resulting arc change was directly proportional to the flow rate, while using the thermal camera to examine the thermal intensity distribution and demonstrating that it is concentrated in the centre, away from the walls at various flow rates, the resulting arc's spectra were also measured. The results show that as the gas flow rate increased, so did the ambient temperature. The results show that the medium containing the arc has a maximum temperature of 34.1 °C at a flow rate of 14 L/min and a minimum temperature of 22.6 °C at a flow rate of 6 L/min. [ABSTRACT FROM AUTHOR]

A gliding arc discharge with an averaged power of 200 W at atmospheric pressure was used to support the supersonic combustion of ethylene fuel with an inflow speed of Mach number 2.92. The instantaneous wall pressure of the combustion chamber and the high-speed CH* chemiluminescence imaging were simultaneously measured to show the characteristics of the gliding arc plasma assistance combustion. The results show that the gliding arc increases the average wall pressure. Specifically, as for the fuel injector near the front step of the cavity, the wall pressure downstream of the aft ramp wall increased at different global equivalence ratios, even increasing the wall pressure upstream of the fore wall of the cavity at an equivalence ratio of 0.1. For the injector away from the fore wall of the cavity, the presence of the gliding arc promotes the wall pressure downstream of the aft ramp wall. In the presence of the gliding arc, the emission intensity and the area of the flame in the cavity are weakened at a low global equivalence ratio (0.10–0.12), whereas the effect is not significant at a range of the total equivalence from 0.15 to 0.2. In the high equivalence ratios from 0.22 to 0.29, the gliding arc plasma plays a significant role in combustion enhancement owing to an increase in the emission intensity and the area of the cavity flame. • A gliding arc (GA) was used to assist combustion in an ethylene-fueled scramjet combustor. • The optical characteristics of the GA assisted combustion were found. • The characteristics of the wall pressure in scramjet combustor with the GA were found. • Comparing the difference of the GA assisted combustion between two injector locations. • The relation between equivalence ratios and the effects of GA was revealed. [ABSTRACT FROM AUTHOR]

Plasma cracking of n-decane is carried out in a new type of gliding arc flow reactor in the atmosphere of nitrogen and air, at a flow range of 25–45 L/min with an interval of 5 L/min. The relationship between arc evolution and discharge voltage and current signals is established by synchronous recording with high-speed camera and oscilloscope. It is recorded that the rotating frequency of the gliding arc is in the range of 81–176 Hz, which increases with the rise of the flow rate and has no direct relationship with the type of gas. When air is used as the discharge medium, although the luminous intensity of the arc is weak, arc rotation is relatively stable, and the specific input energy is higher, which is 58% higher than that of nitrogen. In addition, the partial oxidation of n-decane provides extra heat for cracking, which is helpful to improve the efficiency of plasma cracking. The cracking products mainly include hydrogen, ethylene, acetylene, methane, propylene and ethane. The concentration of each component is higher, reaching the maximum value at the flow rate of 40 L/min, with the hydrogen selectivity of 23.1%. However, when nitrogen plasma is selected, the kinds of products are reduced, containing only hydrogen, ethylene and acetylene, and the concentrations are lower than 0.5%. Two parameters, energy conversion efficiency and carbon based characterization effective cracking rate, were proposed to evaluate the cracking effect of flow reactor. [ABSTRACT FROM AUTHOR]

A gliding arc discharge with an averaged power of 630 W at atmospheric pressure was used to ignite an ethylene-fueled scramjet combustor with an inflow speed of Mach number 2.92. The instantaneous power of the plasma and the high-speed CH* chemiluminescence imaging of the ignition process was simultaneously measured to show dynamic characteristics of the gliding arc plasma-assisted ignition. The results show that the power spikes of the spark-type discharges are the key factor to generate the flame kernel in the scramjet combustor and the instantaneous power can reach 3168 W during the power spikes. The flame kernel ignited by the gliding arc discharge can be developed to form an initial flame, which can become larger with increasing contained discharge energy of the gliding arc. Moreover, a comparison between the successful initial flame and the failed initial flame is performed to demonstrate that the larger area of the successful initial flame can propagate for achieving the mainstream flame, whereas the failed initial flame generated multiple times until the successful initial flame was observed. It is concluded that the successful initial flame contains more discharge energy during the initial flame formation, leading to form the resident flame in the recirculation zone. • A gliding arc (GA) was used to ignite an ethylene-fueled scramjet combustor. • The CH* emission was simultaneously measured with the GA discharge waveforms. • The optical and electrical characteristics of the GA assisted ignition were found. • The evolution process from the flame kernel to the initial flame was found. • The relation between initial flame area and the successful ignition was revealed. [ABSTRACT FROM AUTHOR]

Hydrogen is considered as a clean and promising fuel, and hydrogen production on-board has attracted widespread research attention. In this work, a gliding arc discharge (GAD) plasma reactor was utilized to reform toluene at room temperature and atmosphere pressure. The performance of hydrogen production through oxidative reforming with toluene as raw material under different input power, oxygen to carbon molecular ratio (O/C), residence time and argon addition was investigated. The optimal yields of H 2 and CO (48.6% and 44.3%) were obtained under the condition of the input power of 32 W, the O/C of 0.68, the residence time of 18.4 s and 10 vol% Ar addition. By analyses of spectrum lines and GC-MS, the plasma reforming mechanism of toluene was proposed. It is believed that N 2 (B3Πg) and Ar* could increase the formation of reactive oxygen species (O+, O (1D), O and so on), and N 2 (B3Πg) could impact directly the reforming of toluene. Image 1 • H 2 production via reforming toluene as gasoline surrogate was investigated. • The energy yield and H 2 yield were obtained as 60.2 L·(kW h)−1 and 48.6%. • Toluene reforming mechanism was proposed on emission spectra, gas chromatograph-mass spectrometer. • Excited N 2 , OI and OII atom play main roles in toluene oxidative reforming. • Ar* is beneficial for dissociation of toluene. [ABSTRACT FROM AUTHOR]

The exploration of novel technologies to reduce the air pollution and greenhouse gas emissions has been of great interest. Gliding arc plasma reformer at atmospheric pressure has been developed for converting n-heptane to hydrogen. The system has been evaluated by H 2 yield and energy yield via continuous n-heptane oxidative reforming at room temperature. Effects of some process parameters (discharge gap, input power, residence time, and O/C) have been studied on the reaction performance. The maximum H 2 yield and energy yield are 50.1% and 94.5 L (kW h)−1. To investigate the role of inert gas (N 2 , Ar) in the plasma oxidative reforming system, the performance of C 7 H 16 /air, C 7 H 16 /N 2 /O 2 /Ar and C 7 H 16 /O 2 /Ar have been investigated. The results show that N 2 (B3Π g) and Ar∗ can accelerate the formation of active oxygen species (such as O+, O (1D) and O). The presence of active oxygen species promotes the progress of the oxidative reforming reaction. What's more, N 2 (B3Π g) is also conducive to the direct conversion of n-heptane. The reaction mechanism of hydrogen production from gliding arc plasma oxidative reforming of n-heptane was proposed based on the analysis of the OES and GC–MS. Image 1 • H 2 production from n-heptane reforming in gliding arc plasma was investigated. • The maximum energy yield 94.5 L (kW· h)−1 and yield 50.1% of H 2 were obtained. • The N 2 (B3Π g), O (1D), O+, O play vital role in n-heptane oxidative reforming. • The reaction mechanism was proposed based the analysis of OES and GC-MS. [ABSTRACT FROM AUTHOR]

Nanostructured metal oxides are good candidates for applications in heterogeneous catalysis. Recently our consortium has developed the preparation of such materials by exploiting the redox properties of the non-thermal gliding arc plasma (glidarc) in humid air. This contribution aims at sharing with the community active in the field of heterogeneous catalysis that the glidarc technique is an easy and accessible, but powerful technique with a very bright future that can be used for producing heterogeneous oxide catalysts. Therefore, we present here our most recent achievements in the preparation of titanium, iron and manganese oxide catalysts using glidarc. TiO 2 nanorods containing both rutile and anatase phases with improved photocatalytic activity under visible light were obtained by oxidizing Ti3+ ions in aqueous solution with the plasma species. Fe2+ ions exposed to the plasma discharge were transformed into sea-urchin-like porous goethite (α-FeOOH) nanostructures via the consecutive oxidation-hydrolysis processes. The synthesized goethite was mesoporous with a high surface area. Clay supported catalysts were also prepared by depositing the goethite particles on kaolinite. Those catalysts (and their calcination products) were active in heterogeneous Fenton degradation of organic dyes. α-MnO 2 nanorods were obtained by a rapid reduction of MnO 4 − ions after exposing an aqueous solution of potassium permanganate to the plasma discharge. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The combination of laterite with gliding arc plasma synergistically enhanced pollutant removal. • Laterite was an efficient and stable (photo)catalyst for plasma oxidation of organic pollutant. • Laterite mediated heterogeneous Fenton and photo-Fenton were induced by plasma • Orange G oxidation followed Langmuir–Hinshelwood model. • Laterite catalyst was highly stable after 5 consecutive cycles. Abstract In this study, laterite soil containing various mineral oxides (e.g., Al 2 O 3 , Fe 2 O 3 and TiO 2), used as an alternative catalyst, was combined with gliding arc plasma treatment for Orange G (OG) degradation in aqueous solution. The results showed that the incorporation of laterite soil (as catalyst) in (OG solution exposed to plasma led to a significant degradation enhancement from 17% for plasma treatment alone to almost 100%. Compared with P25 TiO 2 , Fe 2 O 3 , and TiO 2 /Fe 2 O 3 photocatalysts, the decolorization rate of OG can be increased from 56, 68 and 75% respectively to 100% after 60 min laterite-mediated plasma treatment. In the calcinated laterite, Fe 2 O 3 was considered not only as TiO 2 sensitizer due to its narrow band-gap but also as the heterogeneous Fenton catalyst. These synergistically enhanced the generation of the reactive species, i.e., OH, in the gliding arc plasma system and thus process efficiency for OG removal. Under optimized operating conditions, approximately 83% mineralization of OG solution was achieved within 60 min of treatment with the combined process. From the kinetics point of view, OG oxidation fitted with Langmuir–Hinshelwood model with the second-order rate constant (k r) and adsorption constant (K s) of 5.74 mg min−1 and 0.12 L mg−1, respectively, suggesting that the reaction occurs at the catalyst surface. The catalyst was highly stable even after 5 consecutive cycles. [ABSTRACT FROM AUTHOR]

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Iron oxides (FeO x ) supported on clay minerals are efficient catalysts for the Fenton-like degradation of organic pollutants in water. This study explores a new preparation route for such catalysts by exploiting the use of gliding arc plasma at atmospheric pressure for the precipitation-deposition of FeO x particles onto kaolinite. The physicochemical properties of the synthesized catalysts and their activity in the degradation of the azoic dye Acid orange 7 (AO7) are herein evaluated. Results show that the catalysts consist of nanosized goethite fibres onto clay particles. The BET surface area of the catalysts was greater than that of kaolinite and depended on the Fe weight percentage in each catalyst. As a consequence, these materials were very active when tested in the catalytic degradation of AO7 (C 0 = 25 mg L −1 ). Abatement efficiencies of 86% and 50% in terms of bleaching and degradation respectively were obtained after 120 min, in the presence of 0.2 g L −1 of catalyst with 9.4 wt% of Fe. Increasing the catalyst dosage enhanced the abatement efficiency. For the catalyst dosage of 3 g L −1 , the bleaching and degradation efficiencies were 100% and 80% respectively after only 80 min. Moreover, the catalyst was still active in neutral and basic media, even if lower abatement efficiencies were obtained for neutral and basic dye solutions. On the other hand, the AO7 abatement efficiency of catalyst with 4.4 wt% of Fe was almost equal to that with 9.4 wt%, suggesting that 4.4% of iron in the catalyst is sufficient to transform in a reasonable time, all H 2 O 2 into hydroxyl radicals. Finally, the recycling tests showed that the catalysts remain active even after three consecutive uses. [ABSTRACT FROM AUTHOR]

Manganese (IV) oxide (MnO) nanoparticles were synthesized, via a plasma-chemical route by using a gliding arc discharge at atmospheric pressure. α-MnO nanorods were obtained from the chemical reduction of KMnO. The synthesis yield was 96.8% after 4.5 min of exposure of the solution to the plasma. Further increase of the exposure time induced a decrease of MnO yield because of its reductive transformation into Mn ions. Particles were characterized by X-ray powder diffraction, scanning electron microscopy, Fourier Transform Infrared spectroscopy, and nitrogen physisorption. The plasma-catalytic properties of the synthesized material were tested in the bleaching of amaranth red (AR). AR bleaching efficiencies of 17 and 44% were respectively obtained when the plasma and plasma-catalyst processes were applied for 30 min with initial pH 10. The influence of the initial pH, and catalyst concentration were investigated: the AR bleaching efficiency increased linearly with the catalyst concentration and increased markedly when the pH of the solution decreased. [ABSTRACT FROM AUTHOR]

Removal of cationic dye, Azur II, and anionic dye, Reactive Red 2 (RR-2) from aqueous solutions, has been successfully achieved by using a modified agricultural biomaterial waste: cocoa shell husk ( Theobroma cacao) treated by gliding arc plasma (CPHP). The biomass in its natural form CPHN and modified form CPHP was characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and point of zero charge (pH). Experimental variables such as initial pH, contact time, and temperature were optimized for adsorptive characteristics of CPHN and CPHP. The results show that the removal of the Azur II dye was favorable in the basic pH region (pH 10) while the Reactive Red 2 dye was favorable in the acidic pH region (pH 2). The minimum equilibrium time for Azur II and RR-2 dye was obtained after 40 and 240 min, respectively. The adsorption kinetics and isotherm data obtained were best described by a pseudo-second-order kinetic rate model and a combination of Langmuir-Freundlich isotherm models. This work indicates that the plasma-treated raw materials are good alternative multi-purpose sorbents for the removal of many coexisting pollutants from aqueous solutions. [ABSTRACT FROM AUTHOR]

Various iron oxides are used for Fenton reactions to degrade organic pollutants. The degradation efficiency may be improved by transforming an iron oxide phase to another. Here, we report on the transformation of goethite into hematite by thermal treatment at 400 °C. The products were analyzed by X-ray diffractometry, Raman spectroscopy, scanning electron microscopy and N-physisorption. The catalytic activities were measured for orange II bleaching at initial concentration of 25 mg L, pH 3, catalyst concentration of 0.2 g L; 5 mM HO, 30 °C. Results show that the synthesized goethite was successfully transformed into hematite, and the specific surface area of the material increased from 134 to 163 m g. The bleaching efficiency of the orange II dye reached 100 % for the hematite product, versus 78 % for goethite. Therefore, a moderate thermal treatment of a plasma-synthesized goethite improves the catalytic oxidation of organic pollutants. [ABSTRACT FROM AUTHOR]

A Cameroonian kaolinite powder was treated with gliding arc plasma in order to increase the amount of hydroxyl functional groups present on its external surfaces. The functional changes that occurred were monitored by Fourier transform infrared spectroscopy. The crystalline changes were followed by the X-ray diffraction. The ionisation effect, acid effect, and water solubility of the treated samples were also evaluated. Results showed that there is breaking of the bonds in the Si-O-Si and Si-O-Al groups, followed by the formation of new aluminol (Al-OH) and silanol (Si-OH) groups at the external surface of kaolinite after exposing the clay to the gliding arc plasma. The increase in hydroxyl groups on the surface of kaolinite leads to the increase of its hydrophilicity. Moreover, new charges appear on its surfaces and no significant change in crystallinity has occurred. This study shows that clays in powder form being can effectively be functionalised by gliding arc plasma in spatial post discharge processing mode. Knowing that the treatment in spatial post discharge offers the possibility to process large amounts of clay, this work is of great interest to the industry. [ABSTRACT FROM AUTHOR]

• The swirl flame structures of BFG fuel by gliding arc plasma with different equivalence ratios were investigated for the first time. • The experimental result demonstrates that there are six flame structures in the combustion process of blast furnace gas fuel with the decrease of equivalence ratio. • In all cases, the pressure pulsation of blast furnace gas fuel combustion is ± 10 Pa, and there is no obvious dominant frequency of heat release pulsation. • The gliding arc plays the role of anchoring the flame root, to stabilize the combustion of blast furnace gas fuel. As an essential by-product of the iron and steel enterprises, blast furnace gas fuel is used as an alternative fuel for gas turbine combustion to increase economic effect. However, the less combustible components and low heat value of BFG fuel make the combustion in combustor very challenging. In this paper, a gliding arc plasma was employed to assist the blast furnace gas /air combustion with different equivalence ratio. Flame chemiluminescence, the pressure and heat release rate pulsation were recorded simultaneously for showing the flame characteristics of blast furnace gas. The experimental result demonstrates that there are six flame structures in the combustion process of blast furnace gas fuel: A stable flame with short U-shaped (SS-Flame), a vertical oscillating flame (VO-Flame), a stable flame with long U-shaped (SL-Flame), a special gourd-shaped flame (SG-Flame), a lifted flame (L-Flame) and a continuous extinct flame (CE-Flame). According to characteristics of flame structures before flameout, all cases can be divided into three types of extinction modes: I: Direct extinction, II: Oscillation extinction, III: Lifted extinction. The equivalence ratio of extinction limits at the low volume flow rate of air is more likely to be extended by gliding arc plasma than those at the high volume flow rate of air. The pressure and heat release rate pulsation experiment result shows that the violent oscillation of the heat release can be one of the prediction indexes of the flameout of blast furnace gas fuel. In all cases, the pressure pulsation of blast furnace gas fuel combustion is ± 10 Pa, and there is no obvious dominant frequency of heat release pulsation. The amplitude of heat release rate decreases from 0.04 V to 0.01 V with gliding arc plasma addition at φ = 0.7 (E-1 case). Meanwhile, the flame structure of blast furnace gas fuel changes from VO-Flame to SS- Flame due to the gliding arc anchoring the flame root. [ABSTRACT FROM AUTHOR]

[Display omitted] • A carbon bed placed after a Gliding Arc Plasmatron enhances CO 2 conversion. • Achieved O 2 -free and CO-enriched output, beneficial for industrial applications. • Enhanced energy efficiency and lower energy cost. • Importance of oxygen coverage on the carbon surface revealed by means of modelling. CO 2 conversion by plasma technology is gaining increasing interest. We present a carbon (charcoal) bed placed after a Gliding Arc Plasmatron (GAP) reactor, to enhance the CO 2 conversion, promote O/O 2 removal and increase the CO fraction in the exhaust mixture. By means of an innovative (silo) system, the carbon is constantly supplied, to avoid carbon depletion upon reaction with O/O 2. Using this carbon bed, the CO 2 conversion is enhanced by almost a factor of two (from 7.6 to 12.6%), while the CO concentration even increases by a factor of three (from 7.2 to 21.9%), and O 2 is completely removed from the exhaust mixture. Moreover, the energy efficiency of the conversion process drastically increases from 27.9 to 45.4%, and the energy cost significantly drops from 41.9 to 25.4 kJ.L−1. We also present the temperature as a function of distance from the reactor outlet, as well as the CO 2 , CO and O 2 concentrations and the temperature in the carbon bed as a function of time, which is important for understanding the underlying mechanisms. Indeed, these time-resolved measurements reveal that the initial enhancements in CO 2 conversion and in CO concentration are not maintained in our current setup. Therefore, we present a model to study the gasification of carbon with different feed gases (i.e., O 2 , CO and CO 2 separately), from which we can conclude that the oxygen coverage at the surface plays a key role in determining the product composition and the rate of carbon consumption. Indeed, our model insights indicate that the drop in CO 2 conversion and in CO concentration after a few minutes is attributed to deactivation of the carbon bed, due to rapid formation of oxygen complexes at the surface. [ABSTRACT FROM AUTHOR]

Introduction: Candida species are responsible for about 80% of hospital fungal infections. Non-thermal plasmas operated at atmospheric pressure are increasingly used as an alternative to existing antimicrobial strategy. This work investigates the action of post-discharge region of a non-thermal atmospheric plasma jet, generated by a gliding arc reactor, on biofilms of standard strain of Candida albicans grown on polyurethane substrate. Methods: Samples were divided into three groups: (i) non-treated; (ii) treated with argon plasma, and (iii) treated with argon plus air plasma. Subsequently to plasma treatment, counting of colony-forming units (CFU/ml) and cell viability tests were performed. In addition, the surface morphology of the samples was evaluated by scanning electron microscopy (SEM) and optical profilometry (OP). Results: Reduction in CFU/ml of 85% and 88.1% were observed in groups ii and iii, respectively. Cell viability after treatment also showed reduction of 33% in group ii and 8% in group iii, in comparison with group i (100%). The SEM images allow observation of the effect of plasma chemistry on biofilm structure, and OP images showed a reduction of its surface roughness, which suggests a possible loss of biofilm mass. Conclusion: The treatment in post-discharge region and the chemistries of plasma jet tested in this work were effective in controlling Candida albicans biofilm contamination. Finally, it was evidenced that argon plus air plasma was the most efficient to reduce cell viability. [ABSTRACT FROM AUTHOR]

In this study, a template-free synthesis of iron oxyhydroxide nanostructures by gliding arc plasma at atmospheric pressure was evaluated. The results showed that exposure of a Mohr’s salt solution to the plasma discharge induces a rapid oxidation–precipitation of iron(II) into a non-porous and amorphous iron(III) (hydr) oxide. After ageing in temporal post-discharge for three hours, the amorphous iron (hydr) oxide was transformed into crystalline goethite (α-FeOOH). The presence of goethite was confirmed by FTIR, Raman spectroscopy and thermogravimetric analysis. Textural analyses showed that the material is mesoporous with a BET surface area of 134 m 2 g −1 . SEM pictures revealed that the plasma-synthesized goethite particles consist of sea-urchin like hollow spheres. The catalytic activity of such goethite in the Fenton degradation of Orange II (organic dye) showed that this material can be used as heterogeneous catalyst for effective removal of organic pollutants from wastewater. This study establishes that the plasma discharge of gliding arc type can be used as a green and cheap efficient route for the synthesis of porous metal oxide nanostructures. [ABSTRACT FROM AUTHOR]

This study focuses on the discolouration of a triphenylmethane dye (i.e. methyl violet 10B) using a gliding arc plasma discharge in humid air. The results show that the discolouration process is strongly dependent on the initial dye concentration. The maximum discolouration rates are 96.9% and 6.7% after 60 min for initial dye concentrations of 2.5 mg L −1 and 100 mg L −1 , respectively. The incorporation of maghemite (γ-Fe 2 O 3 ) into a 100 mg L −1 dye solution increases the discolouration rate under plasma up to 55.6%. This improvement of the discolouration efficiency suggests that maghemite acts as a heterogeneous catalyst for Fenton decomposition of H 2 O 2 resulting from the dimerization of HO radicals produced by plasma in the gas phase. The X-ray diffraction (XRD) and Fourier transform-infrared (FTIR) characterizations of the catalyst before and after being used 3-times show that the maghemite nanoparticles are stable in the target-solution exposed to gliding arc plasma and can be therefore reused for further treatments. [ABSTRACT FROM AUTHOR]

Hexachlorobenzene (HxCBz) owns the chemical structure of one benzene ring and six H atoms substituted by Cl atoms and it is a persistent organic pollutant present in flue gas from municipal solid waste incineration as an important precursor of dioxins. Its removal was studied using gliding arc plasma treatment, coupled downstream with a V 2 O 5 –WO 3 –TiO 2 catalyst. Several parameters (input voltage, O 2 concentration, catalytic temperature and catalyst position) all influenced its removal efficiency (RE). Optimal parameter settings were tentatively determined, i.e., an input voltage of 15 kV, the temperature of the catalyst (250 °C), and the O 2 concentration (30 vol% O 2 ) tested at a single, fixed concentration of gaseous HxCBz (71.6 ng Nm −3 ). A maximum RE of 76 ± 3% HxCBz was attained, with the plasma and coupled catalyst combined. Two destruction pathways, incorporating dechlorination and oxidation reactions, were recognised, both based on the detection of end- and intermediate products as well as of active species produced by the plasma. These end- and intermediate products included: low chlorinated polychlorobenzenes (mainly 1,2,4-Trichlorobenzene) as well as hydrocarbons (mainly C 2 H 6 ), HCOOH, CH 4 , CO, CO 2 , etc. [ABSTRACT FROM AUTHOR]

• An ammonia combustion device using gliding arc plasma (GAR) reactor was proposed. • GAP reactor combined with swirl burner enhances combustion and reduces NO emission. • Air GAP and ammonia injected from burner swirl ring promoted ammonia combustion. • Ammonia GAP and air injected from swirl ring yielded NO emissions below 100 ppm with ammonia flow rate of 10 SLM. Owing to the high NO x emission and low combustion performance of ammonia fuel, many researchers are exploring new methods for enhancing ammonia combustion performance without the need for blending with other hydrocarbon fuels. In this study, a gliding arc plasma (GAP) reactor was combined with a swirl burner to simultaneously enhance combustion performance and reduce NO emission. The effects of the gas discharge medium, equivalence ratio (φ), and gas flow rate on flame stability, flame speed, and NO emission were investigated. Experimental results show that with air GAP and ammonia injected from the swirl ring of the burner, the optical emission spectrum of the ammonia flame was dominated by the atomic spectrum of O*, H β , and the molecular spectrum of the NH* and OH* components, which significantly promoted ammonia combustion performance, including combustion limitation and NO emission. In addition, with an NH 3 gas flow rate of 10 SLM, optimal NO emission was reduced to approximately 100 ppm, even though the equivalence ratio φ was in a lean flame, and near zero at an equivalence ratio φ larger than 1.6. With ammonia GAP and the air injected from the swirl ring of the swirl burner, online hydrogen from ammonia decomposition was produced by ammonia GAP, and NO emission was always less than 100 ppm for various equivalence ratios φ with an NH 3 gas flow rate of 10 SLM. These results could be used for ammonia combustion with low NO emission, which could be applied to the ammonia fuel industry. [ABSTRACT FROM AUTHOR]

A multi-channel gliding arc (MCGA) plasma was utilized to ignite a kerosene-fueled model scramjet engine with an inflow of Ma2.92. High-speed photography from the top and side view of the scramjet combustor, high-speed CH* chemiluminescence imaging coupled with the electrical measurements were used to investigate the ignition process. A three-dimensional RANS simulation was used to show the distributions of velocity, temperature, and local equivalence ratio of the supersonic cold flow. In the ignition process, the formation of the flame kernel mainly depends on the discharge characteristics of the MCGA plasma, whereas the flame propagation process is mainly determined by the cavity flow. The MCGA plasma is more likely to produce a large area of the flame kernel in the spark-type discharge with the long arc column and overlaps of each channel gliding arc. The larger flame can be generated subsequently by the merging of the flame kernels ignited by the MCGA plasma, which develops into the resident flame. The resident flame is unable to be formed in a relatively high local equivalence ratio, and it is hard to spread to the back of the cavity along the shear layer due to the large velocity gradient with a relatively low temperature. The resident flame is formed several times by the MCGA plasma ignition, which increases the possibility of the flame spreading to the back of the cavity to form the mainstream flame. The local equivalence ratio can significantly affect the cavity ignition of the kerosene-fueled scramjet combustor. [ABSTRACT FROM AUTHOR]

To decompose carbon dioxide, which is a representative greenhouse gas, a 3-phase gliding arc plasmatron device was designed and manufactured to examine the decomposition of CO, either alone or in the presence of methane with and without water vapour. The changes in the amount of carbon dioxide feed rate, the methane to carbon dioxide ratio, the steam to carbon dioxide ratio, and the methane to steam ratio were used as the parameters. The carbon dioxide conversion rate, energy decomposition efficiency (EDE), carbon monoxide and hydrogen selectivity, and produced gas concentration were also investigated. The maximum values of the carbon dioxide conversion rate, which is a key indicator of carbon dioxide decomposition, in different cases were compared. The maximum carbon dioxide conversion rate was 12.3 % when pure carbon dioxide was supplied; 34.5 % when methane was injected as a reforming additive; 7.8 % when steam was injected as a reforming additive; and 43 % when methane and steam were injected together. Therefore, this could be explained that the methane-and-steam injection showed the highest carbon dioxide decomposition, showing low EDE as 0.01 L/min W. Furthermore, the plasma produced carbon-black was compared with commercial carbon-black chemicals through Raman spectroscopy, surface area measurement and scanning electron microscopy. It was found that the carbon-black that was produced in this study has the high conductivity and large specific surface area. Our product makes it suitable for special electric materials and secondary battery materials applications. [ABSTRACT FROM AUTHOR]

Abstract: Pyrolysis and gasification is an energy conversion technology process that produces industrially useful syngas from various biomasses. However, due to the tars in the product gases generated from the pyrolysis/gasification of biomass, this process damages and causes operation problems with equipment that use product gases such as gas turbines and internal engines. Therefore, in this study, a continuous-screw-type pyrolyzer was manufactured and the plasmatron was connected to its rear end through the pyrolyzer. And experiments were performed according to increasing the tar conversion and the hydrogen yield of the product gas. To conduct the parametric studies, experiments were performed on the variations in the steam feed rate, plasma input power and sawdust feed rate (i.e., change for tar concentration in the product gas) to show the performance of plasmatron. The light and gravimetric tars and gases were analyzed to examine the behavior of the products against the hydrogen-rich gas production and tar destruction from the pyrolysis gas. When the steam feed rate of the plasmatron was 1.0 L/min, the plasma input power was 0.17 kW and the sawdust feed rate to the pyrolysis was 0.7 g/min, the conversion rates of the representative light tar components were 80.9% for benzene, 97.6% for naphthalene, 90.7% for anthracene and 90.6% for pyrene. Furthermore, the conversion rate of gravimetric tar was 99.7%. The reformed gas after the plasmatron reaction contained 9% hydrogen, 8.9% carbon monoxide, 2.8% carbon dioxide, 0.55% methane, 0.07% ethylene, 0.01% ethane and 0.12% propane. The hydrogen increased 87.5%, while carbon dioxide decreased 12.5%. [Copyright &y& Elsevier]

A multi-channel gliding arc (MCGA) plasma with 4973 W of the average power was utilized to promote flameholding in an ethylene-fueled scramjet combustor with an inflow of Ma2.92. Schlieren, photography, and CH* chemiluminescence coordinated with electrical and pressure measurements were used to examine the effect of the MCGA plasma on flameholding. The results show that the flame can be basically held by the plasma in the presented experimental conditions, whereas the flame gradually spreads backward in the mainstream and is blown out eventually without the plasma. The MCGA plasma is able to re-ignite the fuel/air mixture with a short period, and the unstable combustion is more likely to be kept by the MCGA plasma for a longer period. The average flameholding time is increased by 51% when the plasma is added. A plausible flameholding mechanism for the flame promoted by the MCGA plasma is revealed that the temperature in the cavity is enhanced by the heat and kinetic effect of the MCGA plasma, decreasing the ignition delay time of the fresh fuel near the cavity ramp, which strengthens the flame stability. [ABSTRACT FROM AUTHOR]