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Some of the authors of the present research group have previously reported mass spectrometric detection of [PdAu9(PPh3)8(CN)]2+ (PdAu9CN) by atmospheric pressure plasma (APP) irradiation of [MAu8(PPh3)8]2+ (PdAu8) in methanol and proposed based on density functional theory (DFT) calculations that PdAu9CN is constructed by inserting a CNAu or NCAu unit into the Au–PPh3 bond of PdAu8 [Emori et al., J. Chem. Phys. 155, 124312 (2021)]. In this follow-up study, we revisited the structure of PdAu9CN by high-resolution ion mobility spectrometry on an isolated sample of PdAu9CN with the help of dispersion-corrected DFT calculation. In contradiction to the previous proposal, we conclude that isomers in which an AuCN unit is directly bonded to the central Pd atom of PdAu8 are better candidates. This assignment was supported by Fourier transform infrared and ultraviolet–visible spectroscopies of isolated PdAu9CN. The simultaneous formation of [Au(PPh3)2]+ and PdAu9CN suggests that the AuCN species are formed by APP irradiation at the expense of a portion of PdAu8. These results indicate that APP may offer a unique method for transforming metal clusters into novel ones by generating in situ active species that were not originally added to the solution. [ABSTRACT FROM AUTHOR]

We report the two-photon absorption laser-induced fluorescence rotational spectrum of the CO B 1Σ+ ← X 1Σ+ Hopfield–Birge system (v′ = 0, v″ = 0) Q-branch in an ∼4850 K, atmospheric pressure plasma torch plume at thermal equilibrium in both the quenching-dominated (low laser intensity) and photoionization-dominated (high laser intensity) regimes. We provide a detailed analysis of the photophysics in these two regimes using a rate equation approach and propose modeling considerations for them as well. In the experimental spectra, distinct rotational transitions up to J″ = 83 are observed, allowing analysis over a very large range of rotational states. Evidence of predissociation is observed for J′ ≥ 64 and is likely due to the interaction with the D′1Σ+ electronic state, which has been proposed in the literature but never observed in the v′ = 0 state. The line positions of higher rotational states show disagreement with line positions calculated from molecular constants in the available literature, suggesting the need for modifications to the constants, which are reported here. A shift in the B 1Σ+ ← X 1Σ+ absorption spectrum toward higher two-photon energy as a result of the second-order Stark shift was observed in the photoionization-dominated spectrum, and the second-order Stark shift cross section was estimated to be 7 ± 3 × 10−18 cm2. The mean photoionization cross section of the excited upper state was inferred by comparing the line broadening of the two spectra and was estimated to be 11 ± 7 × 10−18 cm2. In addition, weak J′-dependent variations of the photoionization cross section were observed and are reported here. [ABSTRACT FROM AUTHOR]

The contribution of atomic nitrogen is fairly possible in plasma-assisted catalytic synthesis of ammonia since it has high adsorption probabilities on solid surfaces. On the other hand, recently, the contribution of vibrational excited molecular nitrogen to ammonia synthesis has been discussed. In this work, we compared the fluxes of atomic nitrogen and vibrational excited molecular nitrogen with the rate of plasma-assisted ammonia synthesis. We employed an atmospheric-pressure nitrogen plasma jet, and the spatial afterglow of the plasma jet and a hydrogen flow irradiated the surface of a ruthenium catalyst. The fluxes of atomic nitrogen and vibrational excited molecular nitrogen were measured by two-photon absorption laser-induced fluorescence spectroscopy and laser Raman scattering, respectively. The synthesis rate of ammonia had a positive correlation with the flux of vibrational excited molecular nitrogen, while the variation of the synthesis rate with the gas flow rate was opposite to the flux of atomic nitrogen. The experimental results indicate the contribution of vibrational excited molecular nitrogen to the synthesis of ammonia using the atmospheric-pressure plasma, where the flux of vibrational excited molecular nitrogen is more than four orders of magnitude higher than that of atomic nitrogen. [ABSTRACT FROM AUTHOR]

The atmospheric pressure pulsed microwave He plasma jet has the advantages of high electron density and abundant active particles, but its shrinking on the discharge electrode morphology limits its application range. In order to modulate a He plasma jet with a longer plume and study its ionization development characteristics, we constructed a dual-channel pulsed microwave coaxial discharge device. He and air were, respectively, injected into the inner and outer gas channels of the resonator to generate a double-layer atmospheric pressure microwave plasma jet with a longer plume. It is observed that the bifurcation of the stratified plasma jet will occur by changing the gas flow. The ionization development of plasma jet was observed by using enhanced charge-coupled device and microwave Rayleigh scattering apparatus measured the space-time evolution of plasma and observed the three times ionization enhancement process of plasma jet development. The spectral lines of the active products associated with Penning ionization were observed by using a fiber optic spectrometer. A fluid model was constructed to simulate and analyze that under the condition of sufficient He flow rate (He flow rate is above 0.6 slm), there will be sufficient and stable He mole fraction (64%) at the stratification of the plasma jet. The experimental and simulation results show that the jet profile of the microwave He plasma is related to the inlet structure of the discharger and He flow rate. Stratified intake structure can produce stratified He plasma jet, and the unique appearance of bifurcation of jet can be produced by changing the flow rate of He. In the bifurcation process of the plasma jet, the product of Penning ionization inhibits the development of the main branch of the plasma jet, and the secondary electron avalanche of the local electric field promotes the formation of the branch of the plasma jet and is accompanied by the enhancement of the second ionization. The ionization mechanism of microwave He plasma is the resonance excitation of local enhanced electric field, the advance of ionizing waves, and the interaction between the spatially distributed active particles. [ABSTRACT FROM AUTHOR]

The growing demand for real-time ultraviolet (UV) monitoring calls for a simple, rapid, and low-cost strategy to prepare UV photodetectors (PDs). We prepare a wearable real-time UV PD based on hydrogenated titanium dioxide film synthesized by radio frequency atmospheric pressure plasma. The conductivity of our hydrogenated titanium dioxide is improved to 10.2 S cm−1, nine orders of magnitude higher than that of pristine titanium dioxide after 10 min plasma treatment. Plasma hydrogenation disrupts the surface crystal structure, introducing oxygen vacancies (OVs) that create self-doped titanium(III) and titanium(II) species. First-principles calculations indicate that the OVs raise the Fermi level of TiO2 and distort the lattice locally. Our optimized film has a distinctive periodic switching characteristic under intermittent illumination; its responsivity is good from 280 to 400 nm, peaking at 632.35 mA W−1 at 365 nm. The fabricated wearable sensor based on the optimized film effectively monitors the daily variation of ambient UV intensity in three typical weather types, transferring its data to a smartphone via Wi-Fi. [ABSTRACT FROM AUTHOR]

Here we report that non-thermal atmospheric-pressure plasma exposure can improve Brassica juncea (leaf mustard) seed germination rate from 50 % to 98 %. The commercially relevant germination rate was achieved by plasma exposure for only 10 minutes and the effect sustains at least for one month under an appropriate storage condition. Improved germination by plasma exposure was also observed for Brassica rapa subsp. pekinensis (Chinese cabbage) seeds. The plasma device used is simple. No pure gas flow system is necessary and it is easy to handle. A large number of seeds can be treated by simply scaling up the device. Plasma exposure can be a practical method for improving seed germination of crop plants important for agriculture. • Non-thermal atmospheric-pressure plasma exposure can improve Brassica seed germination rate. • The effect sustains at least for one month under an appropriate storage condition. • The plasma device used is simple and a large number of seeds can be treated. • Plasma exposure can be a practical method for improving seed germination in agriculture. [ABSTRACT FROM AUTHOR]

Dielectric barrier discharges (DBDs) provide a promising technology for generating non-equilibrium cold plasmas at atmospheric pressure. For both application-focused and fundamental research, it is important to explore the discharge mode transition and electron heating mechanism to enable effective independent tuning of key plasma parameters in a DBD system. In this work, we report numerical studies of the effects of single-frequency excitation on atmospheric argon DBDs, which are carried out in the medium driving frequency (MF) range from 50 kHz to 5 MHz by using a one-dimensional hydrodynamics coupling model. The spatio-temporal evolution of particle density associated with the discharge mode transition and electron dynamic behavior has been investigated. By tuning different components of a single frequency, we observe the electron heating behaviors of the individual modes and mode transitions from the Townsend discharge to the glow discharge in the low frequency to the Ω mode and the hybrid mode in the medium frequency to the α-mode and the γ-mode in the radio frequency. The physical analysis is understood based on these fundamental insights into the plasma physics. [ABSTRACT FROM AUTHOR]

This paper comprehensively explores the integration of machine learning (ML) with atmospheric pressure plasma, highlighting its transformative impact in areas, such as modeling, diagnostics, and applications. The paper delves into the application of neural networks and deep learning models in simulating complex plasma dynamics, enhancing prediction accuracy, and reducing computational demands. We also examine the application of ML in plasma diagnostics, including real‐time data analysis and process optimization, demonstrating advancements in monitoring and controlling plasma systems. The article discusses the challenges encountered in this integration process, such as data quality, computational resources, and model interpretability. Finally, we outline future development directions, emphasizing the potential of ML in revolutionizing plasma research, improving operational efficiency, and opening new avenues in plasma technology. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to check the effectivity of plasma in the natural dyeing of polyester fabric using four natural dyes – Turkey red, Lac, Turmeric and Catechu using plasma and alum mordant. The surface modification on the polyester fabric by plasma along with the use of benign mordant alum is studied. The enhancement of dyeability in polyester fabric with natural dyes is the main focus. Due to surface modification, the wettability increases, which leads to better dye uptake. Better dye uptake and better dye adherence are the main objectives. Design/methodology/approach: Plasma-mediated natural dyeing is the main design of this research work. The effect of plasma treatment on surface modification of synthetic fabric polyester and its subsequent effects on their dyeing with different natural dyes, namely, Turkey red, Lac, Turmeric and Catechu are studied. The dyeability was further enhanced by the use of alum as mordant. The main focus is on the betterment of natural dyeing of polyester fabric using sustainable natural dyes resources for dyeing and to reduce wastewater contamination from the usage of toxic additive chemicals for cleaner production. Findings: Plasma-mediated and alum-mordanted dyeing method facilitated very good dyeability of all the four natural dyes, namely, Turkey red, Lac, Turmeric and Catechu. Color strength (K/S) values and fastness properties of plasma-treated samples were far better than untreated samples. The synergistic effect of plasma and alum mordanting has made natural dyeing of polyester very easy with very good fastness results. Natural dyeing of polyester after 2 min of plasma treatment showed excellent and desirable results. The process is also easy to be adapted by industries. Research limitations/implications: As polyester is hydrophobic, natural dyeing of polyester fabric is not very easy, but with plasma-mediated natural dyeing, it becomes a very facile dyeing method; thus, there are no limitations. Use of plasma has reduced the need for any chemical additives which are usually added during the dyeing process. Practical implications: This process of natural dyeing of polyester fabric can be scaled up to industrial dyeing with natural dyes. Plasma pretreatment of the fabric followed by premordanting with alum has facilitated the natural dyeing well. Social implications: Use of plasma in place of chemical modifiers can be a green and environmentally friendly approach for sustainable coloration of polyester fabric, providing a clean wet processing for textiles dyeing. Originality/value: The synergistic effect of plasma-mediated and alum-mordanted natural dyeing of polyester has not been attempted by any researcher. To the best of the authors' knowledge, this is for the first time that pretreatment with atmospheric plasma followed by alum mordanting of polyester fabric has shown very good dye uptake and fastness properties as the dye molecules could penetrate well after 2 min of the plasma treatment. [ABSTRACT FROM AUTHOR]

Cold atmospheric plasma (CAP) is an emerging technology that can generate various reactive oxygen and nitrogen species (RONS) at room temperature and shows promising applications for skin wound healing. The effects of plasma‐treated medium (PTM) promoting cell proliferation have been verified, but the biological mechanisms involved are not well known. This study aims to assess the proliferation effect and mechanism induced by PTM on human keratinocyte cells (HaCaT) and human umbilical vein endothelial cells (HUVEC) in vitro. The results showed that the concentrations of H2O2 and NO2− inside PTM increased in a time‐dependent manner as the atmospheric pressure plasma jet (APPJ) treatment time was prolonged. The biological outcomes were determined by cell counting kit, wound healing assay, flow cytometry, enzyme‐linked immunosorbent assay (ELISA), and western blot analysis. The cell viability and motility assays indicated that appropriate plasma conditions of short treatment time (15s‐, 30s‐ and 45s‐PTM) could promote cell proliferation, while long treatment time would inhibit cell proliferation (60s‐PTM). With an appropriate time of PTM treatment, the secretion of vascular endothelial growth factor‐α (VEGF‐α) and transforming growth factor alpha (TGF‐α) was promoted and the extracellular signal‐regulated kinase/serine‐threonine protein kinase pathways were activated, which induced HaCaT and HUVEC cell proliferation eventually. These behaviors of cells were mainly related to the enhancement of intracellular reactive oxygen species levels. These findings established a theoretical foundation for potential clinical applications of PTM in wound healing. [ABSTRACT FROM AUTHOR]

Considerable interest has emerged in atmospheric pressure discharges within the microwave frequency range over the past decade, driven by the growing potential applications such as material processing, CO2 dissociation, waste treatment, hydrogen production, water treatment, and so forth. This review delves into the diverse types of atmospheric pressure plasma jets (APPJs) operated at microwave frequencies. The analysis integrates insights from an overall review that encapsulates the different types of geometry, characterizations, modeling, and various applications of microwave atmospheric plasma jets (MW‐APPJs). This paper will contribute to a comprehensive understanding of microwave plasma generated in the ambient atmosphere. The fundamental insights into these discharges are emerging, but there are still numerous unexplained phenomena in these inherently complex plasmas that need to be studied. The properties of these MW‐APPJs encompass a higher range of electron densities (ne), gas temperatures (Tg), electron temperatures (Te), and reactive oxygen and nitrogen species (RONS). This review provides an overview of the key underlying processes crucial for generating and stabilizing MW‐APPJs. Additionally, the unique physical and chemical properties of these discharges are summarized. In the initial section, we aim to introduce the primary scientific characterizations of different types of waveguide‐based and non‐waveguide‐based MW‐APPJs. The subsequent part focuses on the diverse modeling approaches for different MW‐APPJs and the outcomes derived from these models. The final section describes the potential applications of MW‐APPJs in various domains. [ABSTRACT FROM AUTHOR]

In this work, the effect of etching the surface of polymer matrix nanocomposites with atmospheric pressure plasma targeting to achieve enhanced dielectric properties was investigated. Polymer nanocomposites, with varying reinforcing phase content, were modified by atmospheric-pressure plasma resulting in an increase in the surface filler's concentration. Polymethyl methacrylate (PMMA) matrix nanocomposites reinforced with zinc oxide (ZnO) nanoparticles were prepared and dielectrically studied as a function of the nanoparticle content and the plasma modified surfaces. The electrical response of the composite systems was studied by means of Broadband Dielectric Spectroscopy (BDS) over a wide range of temperatures and frequencies. The dielectric permittivity increased with the embedded phase content and with plasma surface treatment. Energy density followed the same trend as dielectric permittivity, and the plasma-treated nanocomposite with the higher ZnO content exhibited approximately 27% higher energy density compared to the unreinforced matrix. [ABSTRACT FROM AUTHOR]

This study reports the effective synthesis of multilayered graphene sheets via microwave atmospheric pressure plasma. This innovative approach streamlines and expedites graphene production and other carbon nanostructures, eliminating the need for catalysts, solvents, or complex processing conditions. Ethanol is directly injected into a microwave-generated argon plasma plume, leading to the formation of graphene. Raman spectroscopy revealed characteristic peaks (2D, G, and D bands) confirming graphene composition, with defects indicated by the D band. X-ray diffraction analysis supported these findings, indicating a broad peak at 25∘ corresponding to the (002) plane, affirming a multi-layered graphene structure. Scanning electron microscopy exhibited crumpled, randomly oriented graphene sheets, albeit with uneven structures suggesting impurity incorporation. The presence of defects was quantified through the intensity ratio of the D to G band (ID/IG) in Raman spectroscopy, revealing a value of 0.80, signifying the presence of defects in the synthesized graphene. The 2D to G band intensity ratio (I2D/IG) suggested the existence of 7–10 graphene layers, highlighting the need for further optimization for enhanced graphene quality and purity. [ABSTRACT FROM AUTHOR]

A method concerning re-use of the main greenhouse gases: CO 2 and CH 4 at the same time producing value-added chemicals (H 2 + CO) is presented in this paper. The method involves the methane dry reforming using an atmospheric pressure operated 915 MHz microwave plasma source with a swirl gas flow. The effect of the CO 2 to CH 4 flow rates ratio, the total gas flow rate and the absorbed microwave power on the volume concentration of the gaseous plasma component in the outlet gas (%), CO 2 and CH 4 conversion rate (%), hydrogen production rate (g h−1) and energy yield of hydrogen production (g kWh−1) was investigated experimentally. The recorded results of the CO 2 and CH 4 conversion rate were about 82% and 88%, respectively. The best results in terms of the hydrogen production rate and energy yield of hydrogen production were equal to 156 g h−1 and 24 g kWh−1, respectively. [Display omitted] • Dry methane reforming using 915 MHz microwave plasma of high gas flows was studied. • Recorded CO 2 and CH 4 conversion rates were up to 82% and 88%, respectively. • Achieved hydrogen production and energy yield of 156 g h−1 and 24 g/kWh, respectively. • CO 2 and CH 4 conversions are comparable with the results obtained at 2.45 GHz plasma. • Results promising for industrial DRM of high gas flow and 915 MHz microwave power. [ABSTRACT FROM AUTHOR]

A novel pulsed power source capable of nanosecond pulses with burst frequencies up to 1 MHz is employed to create atmospheric pressure pulsed plasma in pure CO2 gas. The short bursts contain up to four nanosecond pulses. The CO2 conversion and corresponding energy efficiency are measured ex-situ with Fourier-transform infrared absorption spectroscopy. Trends in the absorption line profile of in-situ quantum cascade laser infrared absorption spectroscopy indicate an elevated vibrational temperature of CO2 with an increasing number of pulses per burst. The key result of this paper is that the dissociation energy efficiency is higher when operating the plasma in burst mode. Furthermore, a larger number of pulses in a burst is associated with a further increase of the dissociation efficiency. The highest efficiency measured is (17.7 ± 0.3) % for single pulses spaced 2 ms apart, and (20.0 ± 0.3) % for bursts of three pulses, with an in-burst frequency of 1 MHz and bursts spaced 4 ms apart. [ABSTRACT FROM AUTHOR]

Long‐term placement of facial implants requires avoiding the formation of fibrous tissue capsules around the artificial material by creating osteoconductive properties of the surface. Most promising approach is the deposition coatings made of materials very similar to bone mineral components, that is, calcium phosphates such as hydroxyapatite (HAp). As part of the research work, an innovative, cost‐effective atmospheric pressure plasma deposition (APPD) system was used as a low‐temperature coating technology for generating the HAp coatings deposition. Full microstructural characterisation of the coatings using SEM and TEM techniques was carried out in the work. It has been shown that the fully crystalline HAp powder undergoes a transformation during the coatings deposition and the material had a quasi‐sintered structure after deposition. The crystalline phase content increased at the coating/substrate interface, while the surface of the HAp was amorphous. This is a very beneficial phenomenon due to the process of bioresorption. The amorphous phase undergoes much faster biodegradation than the crystalline one. In order to increase the bioactivity of the HAp, Zn particles were introduced on the surface of the coating. The TEM microstructural analysis in conjunction with the qualitative analysis of the EDS chemical composition showed that the binding of the Zn particles within the HAp matrix had diffusive character, which is very favourable from the point of view of the quality of the adhesion and the bioactivity of the coating. In the case of such a complex structure and due to its very porous nature, micromechanical analysis was carried out in situ in SEM, that is, by microhardness measurements of both the HAp matrix and the Zn particle. It was shown that the average value of HAp microhardness was 4.395 GPa ± 0.08, while the average value of Zn microhardness was 1.142 GPa ± 0.02 [ABSTRACT FROM AUTHOR]

This document is a compilation of articles that discuss the field of laser materials processing and its applications in various industries. It emphasizes Europe's role in this field and provides an overview of a symposium held during the 2023 Spring Meeting of the European Materials Research Society. The articles cover topics such as laser nanostructuring, up-scaling processing rates, laser direct writing, laser texturing, and surface engineering. The authors provide detailed experimental observations and analysis of their findings, and their biographies highlight their expertise in laser processing. [Extracted from the article]

The use of beam‐based technologies to process optical elements with nanoscale precision enables the fabrication of freeform surfaces. Especially, atmospheric pressure plasma jets (APPJ) have desirable properties such as atmospheric pressure machining, dry processing, and direct writing capabilities. However, the presence of metal oxides in optical glasses leads to the formation of nonvolatile reaction products during APPJ etching with fluorine‐containing gas mixtures, forming a residual layer that increases surface roughness and alters etching behavior. To prevent the formation of the residual layer, the APPJ process is combined with laser cleaning. For a possible future in situ cleaning of the residual layer during the plasma process, laser parameter ranges need to be found to remove the residual layer without damaging the glass surface. Therefore, planar etchings are performed by APPJ on N‐BK7 and Zerodur and the etched planes are subsequently laser irradiated with varying pulse numbers and fluences. The processed samples are then examined by scanning electron microscopy. For both N‐BK7 and Zerodur, a parameter range is identified that results in clean surfaces. The best machining results are achieved with 2–16 pulses and laser fluences of 0.6–1.2 J cm−2 for N‐BK7 and 0.56–0.7 J cm−2 for Zerodur. [ABSTRACT FROM AUTHOR]

This study investigates the mechanism of discharge transitions in a radio frequency atmospheric pressure plasma jet (RF APPJ), with the aim of unraveling the underlying mechanisms behind the unexpected arcing-like filament formation on power electrode observed at lower power levels and the subsequent glow-to-arc transition (GAT) at higher powers. Through meticulous analysis of plasma parameter variations under varying power increment rates, this research offers crucial insights into the complex dynamics of plasma behavior. Detailed analysis of discharge current under different power increment rates exhibited distinct discharge phases as power increased, i.e., the normal glow phase, the abnormal glow phase, and the glow-to-arc transition. Notably, the arcing-like filament formation observed on the power electrode during the abnormal glow phase is indicative of complex plasma dynamics driven by the combined effect of thermal instability and the resulting thermo-field emission. Particularly noteworthy is the dynamic relationship between power increment rates and the duration of the abnormal glow discharge phase, shedding light on the multifaceted nature of thermal instability phenomena. Moreover, the ponderomotive force plays a crucial role in restricting thermo-field emission, thereby preventing the transition from glow to arc at low power levels. Additionally, the observed rise in electron density, electron temperature, and the emission intensity of reactive oxygen and nitrogen species during the abnormal glow discharge phase presents exciting possibilities for novel operational regimes characterized by lower gas temperatures. This study paves the way for enhanced understanding and control of atmospheric pressure plasma processes by highlighting the intricate interplay between power increment rates and discharge behavior, offering promising avenues for developing more efficient and stable plasma-based technologies. [ABSTRACT FROM AUTHOR]

Atmospheric pressure plasma jet (APPJ) has been widely studied for its unique advantages in material surface processing. The exploration of the interaction mechanism between APPJ and material surface is helpful to optimize the surface treatment. In this paper, a 2D axisymmetric fluid model is used to simulate the interaction between APPJ and the dielectric surface driven by negative DC voltage. The effects of the relative permittivity (εr) and roughness of the surface on the evolution of the discharge on the surface of the dielectric are investigated. In this paper, the wave surface composed of semicircles with different radii (R = 0.1 mm, 0.3 mm, 0.5 mm) represents the uneven surface with different roughness, and three sets of values with εr of 1.2, 5 and 80 are selected for simulation. The results show that with the increase of εr, the ionization region shrinks to the center, from a ring region to a solid circular region. When εr increases to 5, corona discharge begins to appear at the central troughs of the dielectric surface. In addition, εr and R together affect the propagation modes of the ionization wave in the grooves in the radial region. With the increase of εr and the decrease of R, the propagation direction of ionization waves in the grooves is reversed. For the distribution of reactive species used to modify the surface of the material, as εr increases, the treatment area begins to shrink toward the center. In addition, the smaller the R, the more uniform the fluxes of reactive species. Therefore, for material surfaces with different εr or R, the modification site, the processing depth and intensity by active particles will change due to changes in the evolution process of APPJ. [ABSTRACT FROM AUTHOR]

Atmospheric pressure plasmas are widely used for nitrogen fixation processes to produce ammonia NH3 or nitrogen oxides NOx, including, for example, nitrite NO2− or nitrate NO3−. Small‐scale atmospheric pressure plasma jets (APPJs) can provide the production of these species on demand at the site of consumption. The species of interest are generated by the plasma and can be dissolved in liquids, for example, to use them. In this work, liquid treatments were performed by an APPJ operated in a He–H2O ${{\rm{H}}}_{2}{\rm{O}}$–N2 ${{\rm{N}}}_{2}$–O2 ${{\rm{O}}}_{2}$ gas composition to investigate the influence of the gas composition on the production of hydrogen peroxide H2O2 ${{\rm{H}}}_{2}{{\rm{O}}}_{2}$, NH3 ${\text{NH}}_{3}$ and NO2‐ ${\text{NO}}_{2}^{ \mbox{-} }$. A validation of two H2O2 ${{\rm{H}}}_{2}{{\rm{O}}}_{2}$ diagnostics showed that the spectrophotometric approach using ammonium metavanadate was interfered by other species when N2 ${{\rm{N}}}_{2}$ was added to the system. Thus, electrochemical sensing of H2O2 ${{\rm{H}}}_{2}{{\rm{O}}}_{2}$ was performed. The concentrations of NH3 ${\text{NH}}_{3}$ and NO2‐ ${\text{NO}}_{2}^{ \mbox{-} }$ were measured by commercially available test kits based on the o‐phythalaldehyde method and the Griess reagent, respectively. At low N2 ${{\rm{N}}}_{2}$ admixtures, the dominant species was H2O2 ${{\rm{H}}}_{2}{{\rm{O}}}_{2}$ with a maximum concentration of 0.9 mM, while NO2− ${\text{NO}}_{2}^{-}$ became dominant at N2 ${{\rm{N}}}_{2}$ admixtures of 0.5% and higher with concentrations of up to 1.5 mM. NH3 ${\text{NH}}_{3}$ was also present in the system and could be measured at low concentrations of less than 0.2 mM in the liquid. By varying the treatment distance and the gas flow rate, insights into the transport phenomena of the species and their dissolution into the liquid could be gained. Low‐frequency pulsing of the radio frequency (RF) jet led to an accumulating effect on H2O2 ${{\rm{H}}}_{2}{{\rm{O}}}_{2}$, a reduced production of NO2− ${\text{NO}}_{2}^{-}$ and a switch from NOx ${\text{NO}}_{x}$‐dominated production to H2O2 ${{\rm{H}}}_{2}{{\rm{O}}}_{2}$‐dominated production. [ABSTRACT FROM AUTHOR]

In order to improve the surface flashover strength of the insulation materials and solve the problem that the relatively high price of CF4 restricts the large-scale application of fluorination modification of CF4 atmospheric pressure plasma jet (APPJ) in the industrial field, He/CF4/O2 APPJ with different O2 content is used to treat epoxy resin (EP) dielectric material. By analyzing the results of scanning electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy, the influence of O2 content on the multiple characteristics of EP surface before and after APPJ treatment is studied. Flashover experiment is also carried out on EP surface before and after APPJ treatment. It is found that the addition of 0.1% O2 can increase the mature voltage of the EP surface by about 16.10% compared with untreated EP surface. It is concluded that the improvement of the surface flashover strength with a small amount of O2 (within 0.1%) is influenced by the surface roughness and chemical composition of the dielectric. The deposition effect of APPJ on EP surface is enhanced to increase the surface roughness and reaches the best at 0.1% O2, because the addition of excessive O2 will weaken the APPJ intensity. It is speculated that the creepage distance of the EP surface is increased to inhibit the formation of electron collapse and the content of electronegative fluorine and oxygen on the EP surface is increased under a small amount of O2 addition, resulting in the inhibition of the formation of surface flashover. [ABSTRACT FROM AUTHOR]

Interactions of floating potential on metal and dielectric targets with He atmospheric pressure plasma jet (APPJ) were studied in this paper. The APPJ is generated in a needle-ring corona-dielectric barrier discharge configuration, driven by a sinusoidal voltage. The characteristics of APPJ were assessed through electrical and optical examinations, and the time-average electrostatic voltage on the targets was measured using both contact and non-contact electrostatic voltmeters. It was found that both metal and dielectric targets can promote the jet development and speed up the jet velocity. During the negative half-cycle, the "plasma cluster" propagates from the target toward the ground electrode and then "merges" with the forward plasma jet, leading to a reversed development of jet. The two targets follow a similar pattern on the surface electrostatic voltage, that is, initially in a positive polarity whose amplitude first increases and then decreases and transits to negative polarity with an increase in the applied voltage. But there are also some minor differences between the two targets, e.g., the metallic target can change the discharge pattern and reduces the discharge current under certain conditions. [ABSTRACT FROM AUTHOR]

Uneven dyeing results from the different ways the fibers in a blended fabric made of viscose and cotton (50/50) absorb reactive dyes. Measuring the color levelness continues to be an obstacle for dyers. In the present study, several color levelness measurements are analyzed in particular. In addition, the functional group on the outer structure of the viscose-cotton blended fabric has been developed using air plasma to enhance the color intensity. The blended fabric was exposed to an air-based plasma treatment at an atmospheric pressure of 0.15 Tor for varying durations (2, 4, 6, 8, and 10 min). Furthermore, the existence of the functional groups in the blended fabrics treated with plasma (-OH, -COOH) was examined by FT-IR analysis. SEM and an optical microscope confirmed that the blended fabric had undergone surface deformation due to plasma treatment. The hydrophilicity of the Viscose-Cotton blended fabric was enhanced by plasma treatment and consequently, the maximum dye exhaustion of 85% (C.I. Reactive Red 195) and 65% (C.I. Reactive Blue 21) was reached. The degree of color levelness was determined through extensive experimental tests using an instrumental method and color difference (ΔE) data. Additionally, utilizing the image J software enabling the analysis of images, the levelness of colored blended fabric was further measured. The levelness values for the untreated viscose-cotton blended fabric dyed with C.I. Reactive Red 195 and C.I. Reactive Blue 21 were 4.11 and 4.26, respectively. After 6 min of plasma treatment, the viscose-cotton (50/50) blended fabric exhibited excellent levelness with values between 4.94 and 4.91. [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]

Dermanyssus gallinae, the poultry red mite (PRM), is a hematophagous temporary ectoparasite that causes serious economic losses and animal health impairment on laying hen farms worldwide. Control is limited by the parasite's hidden lifestyle, restrictions on the use of chemical acaricides and the development of resistance against certain drug classes. As a result, research was conducted to explore alternative control methods. In recent years, atmospheric pressure plasma has been increasingly reported as an alternative to chemical acaricides for pest control. This physical method has also shown promising against PRM under laboratory conditions. However, the detailed mechanisms of action have not yet been elucidated. In the present study, the effects of cold atmospheric pressure plasma on PRM were investigated using digital videography and optical coherence tomography (OCT), an imaging technique that visualizes the topography of surfaces and internal structures. Digital videography showed that a redistribution of the contents of the intestinal tract and excretory organs (Malpighian tubules) occurred immediately after plasma exposure. The body fluids reached the distal leg segments of PRM and parts of the haemocoel showed whiter and denser clumps, indicating a coagulation of the haemocoel components. OCT showed a loss of the boundaries of the hollow organs in transverse and sagittal sectional images as well as in the three-dimensional image reconstruction. In addition, a dorso-ventral shrinkage of the idiosoma was observed in plasma-exposed mites, which had shrunk to 44.0% of its original height six minutes after plasma exposure. [ABSTRACT FROM AUTHOR]

1,2,3,4,5,6,7,8‐Octamethylcyclotetrasilazane (OTMSD), a cyclic silazane precursor, is deposited via atmospheric pressure plasma onto a substrate. The resulting coating exhibits a dual surface roughness, contributing to a significant reduction of surface wettability. Notably, the coating exhibits superhydrophobic characteristics, proven by a water contact angle of approximately 170°, hysteresis angle below 10°, very low tilting angle (<10°), and droplet‐bouncing effect. Importantly, this superhydrophobicity is achieved using OTMSD as fluorine‐free precursor with low reactivity to water. Furthermore, the deposition process is carried out using a commercially available plasma device highlighting its practicality and scalability for large‐scale production. [ABSTRACT FROM AUTHOR]

During atmospheric pressure plasma impingement, plasma induced liquid flow will influence the transport and distribution of plasma generated charged and reactive species in liquids. We use particle image velocimetry and supplementary pH, conductivity and temperature measurements to investigate electrical properties of an AC kHz plasma jet interacting with water and electrolytes. We observe that the dominant driving mechanism in low conductive solutions are surface forces such as shear stresses and stagnation-pressure induced dimpling. These give upwards flows beneath the plasma–liquid interaction point. In highly conductive solutions, such as water with dissolved salts, the dominant driving mechanism is electro-hydrodynamic forces, with flows directed downwards underneath the plasma jet in our system. We therefore demonstrate that the direction of initial plasma induced liquid flows can be controlled through the addition of salt ions. In electrically grounded salt solutions, we also observe time resolved flow direction switching, possibly due to modification of salt solutions via electrolytic and plasma induced reactions changing the dominant flow mechanism over time. [ABSTRACT FROM AUTHOR]

Polymer film capacitors experience a sharp decrease in charge–discharge efficiency and energy density under high‐temperature environments, which remains an urgent issue to address. In this article, atmospheric pressure plasma jet (APPJ) is used to deposit TiO2 to improve the energy storage performance of biaxially oriented polypropylene (BOPP) film in high‐temperature environment. The APPJ uses argon as the working gas and adopts a multielectrode grounding configuration to obtain the stable jet state. The precursor solution is prepared using tetraethyl titanate (TET) mixed with ethanol in a ratio of 5:3. The results show that the charge–discharge efficiency and discharge energy density (from 3.1 to 5.7 J cm–3) of BOPP films deposited by APPJ are improved at 120°C. [ABSTRACT FROM AUTHOR]

Microfluidic systems have become integral for lab‐on‐a‐chip and organ‐on‐a‐chip applications across numerous disciplines. These systems, typically fabricated using polydimethylsiloxane (PDMS) chips on glass substrates, lack the bioactivity required for such applications. To overcome this, biomolecules are immobilized using either oxygen (O2) plasma treatment or chemical reagents like amino silanes. However, O2 plasma treatments are unstable and cannot covalently immobilize biomolecules, while wet‐chemistry approaches are toxic, time‐consuming, and expensive. A novel microfluidic platform that combines two plasma surface treatments: Plasma‐activated coating (PAC) and atmospheric pressure plasma jet (APPJ), to enable reagent‐free covalent immobilization of biomolecules is described here. These surface treatments, unlike O2 plasma, covalently immobilized fibronectin on PDMS and glass, and significantly improved endothelial cell attachment and proliferation. By combining PAC and APPJ, a hybrid microfluidic platform with equivalent bond strength to standard O2 plasma devices, but with significantly enhanced endothelial cell growth in and artery‐on‐a‐chip model, is developed. This platform is also amenable to high‐shear applications such as coronary shear, with endothelial cells aligning with flow, as seen in human arteries. By providing reagent‐free covalent immobilization of biomolecules within a microfluidic system, this technology has the potential to radically improve organ‐on‐a‐chip development as well as lab‐on‐a‐chip systems, point‐of‐care diagnostics, and sensors. [ABSTRACT FROM AUTHOR]

The Z-pinch device is a critical component in inertial confinement fusion, where stainless steel electrodes must withstand high current densities of up to MA/cm2. Gases and difficult-to-remove impurities adhering to the electrode surfaces can ionize, significantly impacting the device's electrical conductivity efficiency. In this paper, the surface of stainless steel electrodes was subjected to cleaning using a large-area plasma jet under atmospheric pressure. The wettability, chemical composition, and chemical state of the electrode surface were characterized using a water contact angle measuring instrument and X-ray photoelectron spectroscopy (XPS). The cleaning effect under different discharge parameters was systematically analyzed. The results revealed a significant reduction in the content of carbon pollutants on the surface of stainless steel electrodes, decreasing from 62.95% to a minimum of 37.68% after plasma cleaning. Moreover, the water contact angle decreased from 70.76° to a minimum of 29.31°, and the content of water molecules adsorbed on the surface decreased from 17.31% to a minimum of 5.9%. Based on the evolution process of micro-element content and chemical state on the surface of stainless steel electrode, the cleaning process of adhering substances on the surface by atmospheric pressure plasma was analyzed by the layered cleaning model for surface pollutants on stainless steel. [ABSTRACT FROM AUTHOR]

Plasma jets, crucial atmospheric pressure sources in biomedical applications, generate reactive species in liquids, with electrical fields playing a significant role, as variations in pulse rise times and durations in dielectric barrier discharges yield diverse effects. This study presents a novel nanosecond pulse plasma jet. Here, investigations with phosphate‐buffered saline and Ringer's saline elucidate critical parameters influencing species generation, such as treatment time and gas flow rate. Results showed increasing concentrations of H2O2 and NO2− over time, with NO2− degrading faster in Ringer's saline due to acidification. The nanosecond pulse jet exhibits superior energy efficiency than conventional jets, laying the groundwork for optimizing species generation and studying electrical field effects in future biological works. [ABSTRACT FROM AUTHOR]

Fluoropolymer films were treated by atmospheric pressure nitrogen plasma in a roll-to-roll configuration. This treatment aimed to modify the surface properties of the fluoropolymer and assess its adhesion with commercial silicone, rubber, and acrylic adhesive tapes. Fluoropolymer films and adhesives were characterized using contact angle measurements, Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS), and T-peel tests. The plasma treatment resulted in increased wettability of the films, defluorination of the fluoropolymer surface, the introduction of oxygen- and nitrogen-containing functional groups on the surface, and a reduction in surface roughness. Peel strength increased at different levels, depending on the treatment speed and adhesive employed. Silicone adhesives did not present a significant increase on plasma-treated fluoropolymer films; however, they presented the higher peel strength against the untreated substrate. Acrylic adhesives are sensitive to fluoropolymer surface chemistry and can be used to evaluate different plasma treatments, while the highest adhesion was obtained with rubber adhesives. The results presented herein provide information about the appropriate selection of the type of adhesive for a specific application, as well as the evaluation of surface modifications by T-peel test. [ABSTRACT FROM AUTHOR]

Generating a uniform non-equilibrium plasma in atmospheric pressure air has always been a challenge. It is believed that the maximum spacing for generating a uniform non-equilibrium plasma in atmospheric pressure air, whether using AC or nanosecond pulse drive, is 4 mm. Discharges are always non-uniform when the spacing is greater than 4 mm. In this paper, we propose a new type of dielectric barrier discharge structure to address this challenge. The left end of the structure rapidly increases the discharge spacing from 0.5 mm to 6 mm, while the right side of the main discharge gap maintains a uniform spacing of 6 mm. Nanosecond pulse voltage is used to drive the plasma, an ICCD camera is used to capture the image of the plasma during a discharge pulse cycle, which indicates that a uniform plasma within the 6 mm spacing of the main discharge gap is generated. Upon further reducing the ICCD camera's exposure time to 20 ns, it is revealed that the uniform plasma is formed due to the rapid propagation of the plasma from left to right at a speed of order of 105 m s−1. Due to the small transverse component of the external electric field, this rapid propagation behavior cannot be due to the external electric field. Therefore, this paper further proposes the hypothesis of electric dipole formation leading to this fast propagation. The hypothesis suggests that the charge separation on the surface of the anode forms an electric dipole, which generates a local discharge at its right end. This local discharge further triggers the discharge in the main gap, and the main gap discharge, in turn, forms a dipole due to charge separation again, by repeating this cycle, the plasma propagates rapidly to the right. Further analysis demonstrates that this dipole can indeed produce a strong electric field of up to 41 kV cm−1 at its right end, which is sufficient to induce a local discharge. Moreover, under such a strong electric field, the electron migration rate can indeed reach 105 m s−1. These findings support the plausibility of this hypothesis. [ABSTRACT FROM AUTHOR]

In this article, a compact and portable microwave atmospheric pressure plasma jet (MW‐APPJ) generator based on a coaxial transmission line resonator (CTLR) was proposed. Based on the electromagnetic simulations, the jet generator was designed as a tapered inner conductor structure that ensures plasma generation at low power. A self‐igniting argon (Ar) plasma jet of 10 mm length was generated at an input power of ~20 W and maintained at 2 W. Thanks to the high efficiency of the CTLR structure, plasmas of mixed reactive gases were also realized. Intrinsic plasma parameters and active species were determined using optical emission spectroscopy. Furthermore, the MW‐APPJ device was used to modify the polytetrafluoroethylene surface, and improvement of hydrophilicity was achieved without thermal damage. [ABSTRACT FROM AUTHOR]

In this work, a new geometry Helium Cold Atmospheric-pressure Plasma (CAP) jet operated using bi-polar pulsed power source is reported. Its effectiveness in disinfecting E. faecalis infected root canals is evaluated and compared to that of 5.25% NaOCl and QMix at various time intervals. Before treatment, the jet has been characterized electrically and accordingly optimized for different operating parameters. Kruskal–Wallis Rank Sum and Wilcoxon tests are performed to analyse the difference among all the treatment groups. The CAP jet has shown maximum antibacterial efficiency at 10 min of exposure. CAP Jet, NaOCl, and QMix treatment achieved maximum percentage reductions of 90.8%, 99.99% and 96%, respectively. However, NaOCl and QMix have several disadvantages. It is predicted that the controlled exposure of CAP jet can be used as root canal disinfectant and best optimized further as a non-intrusive method. [ABSTRACT FROM AUTHOR]

In this study, we employed an atmospheric-pressure non-thermal plasma jet that used silver nitrate solution as the precursor which is injected, in an aerosol state, into the plasma jet to create silver nanoparticles with the desired distribution on the glass substrate. The crystal structure and morphology of the Ag nanoparticles printed on the glass substrate were characterized by X-ray diffraction (XRD), the field emission scanning electron microscope (FESEM), and the atomic force microscope (AFM). The XRD patterns confirm Ag nanostructure deposition on the glass. FESEM results show that Ag nanoparticles' are almost spherical in shape and by increasing the applied voltages, the Ag nanoparticles' size and density increases, and AFM images confirm the results of FESEM images. Rhodamine B with various concentrations was employed to determine the surface-enhanced Raman scattering (SERS) performance of Ag nanoparticles printed on the glass. It shows high sensitivity for Ag layers created by plasma to a threshold that even for the lower concentrations of 10−10M, Rhodamine B is still detectable. There was the optimum SERS effect at a 7 kV voltage. Also, the plasma-printed Ag layers are able to detect methylene blue, usually used as a fungicide in fish ponds and aquariums, even in low concentrations of 10−9M. The residual sulfur dioxide (SO2) of raisins was detected using a plasma-printed silver layer. This shows the application of this plasma-printed silver layer for residual SO2 detection in the food industry. [ABSTRACT FROM AUTHOR]

Released in March 2023, GPT‐4 has shown remarkable proficiency in various scientific areas, including atmospheric pressure plasma research. The paper discusses how GPT‐4, supported by ScholarAI and Wolfram plugins, enhances research efficiency with its vast knowledge and inferencing skills. It focuses on plasma‐water‐based nitrogen fixation experiments, demonstrating GPT‐4's abilities in explanation, analysis, prediction, planning, and verification. The study also addresses challenges like interpreting non‐textual data and keeping pace with scientific advancements. It highlights GPT‐4's role in improving nitrogen fixation process efficiency, showcasing its utility in scientific analysis and decision‐making. The paper emphasizes the evolving role of AI in research and the need for the scientific community to adapt to the rise of more advanced AI systems. [ABSTRACT FROM AUTHOR]

Atmospheric pressure plasma deposition (APPD) of poly(ethylene oxide) (PEO)‐like antifouling coatings provides an attractive way to reduce biofouling for reliable biosensor operation. Cold atmospheric pressure plasma jets are designed to operate in open air. This paper demonstrates the impact of open‐air processing on the composition and properties of PEO‐like coatings by APPD with vinyl ether precursors. The open‐air environment inhibits polymerization as indicated by low deposition rates, oxygen incorporation in the coatings, and instability of the coatings in water. The composition and stability of the coatings improve by appropriate nozzle design and by deposition in an environment with lower air content. The resulting PEO‐like coatings are stable and antifouling for an antibody solution and inhibit adhesion of human fibroblast cells. [ABSTRACT FROM AUTHOR]

Non-thermal plasma (NTP) conversion applications have become an emerging technology of increasing global interest due to their particular ability to perform at atmospheric pressure and ambient temperature. This study focuses on a specific case of a dielectric barrier discharge NTP reactor for carbon dioxide conversion with the usage of argon as diluent gas. The plasma computations in COMSOL® Multiphysics are compared to experimental results and coupled with previous thermodynamic characterization of argon species and fluid dynamic calculations. The model is defined as a time-dependent study with a 2D-Geometry of pure argon, with both fluid flow and plasma phenomena. Firstly, the model showcases an accurate understanding of the plasma physics involved, in the form of electron density, excited argon, argon ions, and mean electron energy. It also allows a direct comparison of the velocity, vorticity, pressure, and dynamic viscosity results with fluid flow computations. Secondly, the impact of several variables is studied, notably the inlet volumetric rate, dielectric barrier thickness and material, and reactor length. Limitations in the plasma characterization can occur by not including packed material or all relevant species in experimental CO2 conversion and their respective reactions, which should be aimed at in future contributions. [ABSTRACT FROM AUTHOR]

In this work, the productions of reactive oxygen and nitrogen species (RONS) with duty ratio in atmospheric pressure plasma jet was studied. This study uses the duty ratio comprising an on-time duration with a sinusoidal voltage bunch and an off-time duration without any voltage bunch for the plasma jet operation. The reactive species NO, NO2, N2O, and O3 were measured in the plasma jet in accordance with the duty ratio by gas-FTIR and ozone meter. The NOx are the mainly produced in the plasma jet due to the high temperature, and all reactive species exhibited increased production when increasing the duty ratio. But, under the fixed duty-ratio of 10%, reactive species were different trends by the on-time duration. Although there was no additional dissipated power at a given duty ratio, NO production enhanced by 1.5 times, whereas the production of the other species decreased with increasing on-time duration. These phenomena were explained by measured rotational temperature with on-time in this experiment. [ABSTRACT FROM AUTHOR]

The paper presents a novel method for obtaining cobalt ferrites with a spinel type structure under the action of a nonequilibrium atmospheric pressure gas-discharge plasma in air on a mixture of solid iron and cobalt hydroxonitrates. The data of energy dispersive X-ray spectroscopy and X-ray phase analysis showed that the synthesized powders have a complex phase and chemical composition, which depends on the Fe:Co molar ratio in the initial salts. The best result in terms of yield of cobalt ferrite is obtained with Fe:Co = 2:1. The resulting material contains 86 wt% Fe2CoO4, also 13.5 wt% Fe2O3 and 0.5 wt% Fe3O4. At other ratios, Co3O4 is also formed. According to dynamic light scattering data, the obtained powders consist of two characteristic fractions. The main fraction (94%) is represented by particles 105 ± 4 nm in size. And the other fraction (6%) consists of particles 18 ± 4 nm in size. The resulting materials have magnetic properties. So, for powders obtained from salts with Fe:Co = 2:1 the coercive force was 490 Oe. The saturation magnetization was 52 emu/g, and the remnant magnetization was 22 emu/g. [ABSTRACT FROM AUTHOR]

We present a new food processing method to increase the content of polyphenols, which are a type of health-promoting food component, in harvested onions using atmospheric-pressure low-temperature plasma technologies. Harvested onions were locally irradiated for different times with a low-temperature air plasma jet generated near atmospheric pressure and stored in the dark for various periods. The plasma-irradiated area was 7 mm2. The plasma irradiation was performed without removing the onion peel. After storage following plasma irradiation, the onion was peeled and cut into the outer, middle, and inner parts, analysing polyphenol content at each edible onion part, namely the bulb. The polyphenol content in the onions irradiated for 30 min and stored for 3 d increased over that of unirradiated onions stored for the same period. This increase occurred regardless of the bulb parts. Neither the plasma-irradiated onions without storage nor the air gas-irradiated onions without air plasma irradiation exhibited a higher polyphenol content. In particular, quercetin aglycone, quercetin 4′-O-glucoside, quercetin 3-O-glucoside, and quercetin 3,4′-O-glucoside were increased in the polyphenol content, contributing to an increase in the antioxidative activity. NO3− and NO2− were introduced into water under an onion peel by air plasma irradiation for 30 min and decreased after 3 d of storage but remained. However, no H2O2 was introduced. The plasma-introduced NO3− was distributed throughout the onion owing to the plasmodesmata serving as channels for cell-to-cell transports of molecules. These results suggest that the increased polyphenol content originates from the transcriptional factors acting in stress responses to the plasma-introduced NO3− and NO2−, not the electric field-induced electroporation, in onion cells. The present study provides valuable insights into interactions between low-temperature air plasma jets and onion cells. [ABSTRACT FROM AUTHOR]

This study explores the use of air-fed atmospheric pressure plasma jets (APPJs) as a pre-joining treatment for 3D carbon fiber-reinforced carbon matrix composites (C/C) with the aim of both creating a textured surface that resembles a brush structure and improving the joint strength. The effects of various treatment time lengths on the mass loss, etching depth, and surface texture were investigated using SEM and confocal microscopy. An optimal process time of 30 s was selected, while keeping the other process parameters fixed (air flow of 1750 l/h and nozzle-sample distance of 5 mm). Wetting tests were conducted at 1000 °C, on both untreated and pre-treated C/C surfaces by means of liquid TiCuNi brazing alloy, and low contact angles of about 20° were measured. C/C–TiCuNi–C/C and C/C–TiCuNi–Cu joints were then produced, and their interfacial reactivity was evaluated. The apparent shear strength measured for the APPJ-treated C/C–Cu joints was 140 % higher than the value recorded for the untreated joints, thus confirming the effectiveness of the treatment. Even though a further investigation is needed in which an optimization of the process parameters should be included, this preliminary study has revealed the viability of APPJ as a promising technique to enhance the bonding of C/C composites in dissimilar assemblies and to improve the joint quality. [ABSTRACT FROM AUTHOR]

This study presents atmospheric‐pressure plasma as a novel catalyst‐free pretreatment method for raw wheat straw (RWS) biomass. The work explores the effects of processing parameters, such as milled particle size, moisture content of RWS, and plasma generations, on pretreatment efficiency. To understand the mechanisms behind the enhanced pretreatment efficiency, various analysis techniques were used to analyze the physical and chemical properties of RWS before and after pretreatment. The analysis reveals that plasma pretreatment significantly damages the surface smoothness of RWS and enhances the decomposition of lignocellulosic structures. These effects are primarily attributed to the reactive species generated by the pulsed discharge, rather than the accompanying UV radiation, acidification, or heating actions during plasma pretreatment. [ABSTRACT FROM AUTHOR]

Atmospheric pressure cold plasmas have recently been the subject of intense research and applications for solving problems in the fields of energy, environmental engineering, and biomedicine. Non-thermal atmospheric pressure plasma sources, with dielectric barrier discharges, plasma jets, and arc discharges, are non-linear power loads. They require special power systems, which are usually designed separately for each type of plasma reactor, depending on the requirements of the plasma-chemical process, the power of the receiver, the type of process gas, the current, voltage and frequency requirements, and the efficiency of the power source. This paper presents non-linear phenomena accompanying plasma generation in the power supply plasma reactor system, such as harmonic generation, resonance, and ferroresonance of currents and voltages, and the switching of overvoltages and pulse generation. When properly applied, this can support the operation of the above-mentioned reactors by providing improved discharge ignition depending on the working gas, thus increasing the efficiency of the plasma process and improving the cooperation of the plasma-generation system with the power supply. [ABSTRACT FROM AUTHOR]

NO synthesis using plasma catalysis is analyzed in a parallel-plate atmospheric pressure RF plasma from N2/O2 admixed to helium exposed to Fe and Pt catalysts on a SiO2 support. The NO x species are measured by Fourier-transform infrared spectroscopy in a multi-pass cell. The trends in species densities can be well explained by air chemistry reactions, where NO's progressive oxidation occurs with increasing oxygen admixture and ozone generation. The sequence can be controlled by the state of the surface that preferentially quenches O3 and allows for an optimum NO production. The maximum production of NO is found at 70% N2/(N2+O2) mixture ratio at 120 ∘C using sandblasted glass, with a conversion rate of 0.085%. [ABSTRACT FROM AUTHOR]

In this study, an improved PVA/PLA fibrous hemostatic membrane was prepared by electrospinning technology combined with air plasma modification. The plasma treatment was used to modify PLA to enhance the interlayer bonding between the PVA and PLA fibrous membranes first, then modify the PVA to improve the hemostatic capacity. The surfaces of the PLA and PVA were oxidized after air plasma treatment, the fibrous diameter was reduced, and roughness was increased. Plasma treatment enhanced the interfacial bond strength of PLA/PVA composite fibrous membrane, and PLA acted as a good mechanical support. Plasma-treated PVA/PLA composite membranes showed an increasing liquid-enrichment capacity of 350% and shortened the coagulation time to 258 s. The hemostatic model of the liver showed that the hemostatic ability of plasma-treated PVA/PLA composite membranes was enhanced by 79% compared to untreated PVA membranes, with a slight improvement over commercially available collagen. The results showed that the plasma-treated PVA/PLA fibers were able to achieve more effective hemostasis, which provides a new strategy for improving the hemostatic performance of hemostatic materials. [ABSTRACT FROM AUTHOR]

Today, aramid fibers are well known as a high‐performance and ideal material for reinforcement purposes in rubber product manufacturing including hoses, tires, cables, and conveyors composites. However, surface modification of aramid fiber is necessary to solve poor interfacial adhesion between aramid fibers and the rubber matrix. Accordingly, in the present study, the effect of the surface modification of aramid fibers using atmospheric pressure plasma treatment with different precursors on adhesion to the rubber matrix was investigated. For that, the plasma coating was conducted using argon as the main working gas, and toluene, acetonitrile, tetraethyl orthosilicate (TEOS), and hexamethyldisiloxane (HMDSO) as liquid precursors. The physical–chemical characterization of the layer confirmed the successful deposition of amorphous carbon, amorphous nitride‐carbon, SiO2, and Polydimethylsiloxane (PDMS)‐like coating layers on the surface of aramid fibers by using toluene, acetonitrile, TEOS, and HMDSO as precursors, respectively. Overall, the result showed that the plasma surface modifications with acetonitrile precursor leads to the increase in interfacial adhesion of aramid/rubber composite, while retaining the tensile strength, and flame resistance properties of aramid as original fibers. Notably, the results of this study confirm the potential use of atmospheric pressure plasma for surface modification of aramid yarn to produce functional aramid for use in rubber composites. Highlights: The plasma‐coated aramid using HMDSO, TEOS, toluene, and acetonitrile precursors was prepared; and its effect on the tensile properties of aramid fiber as well as interfacial adhesion between aramid/rubber composite was investigated.The positive effect of atmospheric pressure plasma coating using HMDSO precursor on the tensile properties of aramid fiber was revealed.The positive effect of atmospheric pressure plasma coating using toluene and acetonitrile on the interfacial adhesion between aramid/rubber composite was revealed.The positive effect of atmospheric pressure plasma coating using TEOS precursor on the flam resistance property of aramid fiber was revealed.This study provides valuable insights into the effect of the different plasma‐coated organosilicon and hydrocarbon precursors on the interfacial adhesion between aramid/rubber composite. [ABSTRACT FROM AUTHOR]