Application Of Low-temperature Plasma Research Articles

A comparative study on the spectral characteristics of nanosecond pulsed discharges in atmospheric He and a He+2.3%H2O mixture

Nanosecond pulsed discharges at atmospheric pressure in a pin-to-pin electrode configuration are well reproducible in time and space, which is beneficial to the fundamentals and applications of low-temperature plasmas. In this experiment, the discharges in helium (He) and He with 2.3% water vapor (H2O) are driven by a series of 10 ns overvoltage pulses (~13 kV). Special attention is paid to the spectral characteristics obtained in the center of discharges by time-resolved optical emission spectroscopy. It is found that in helium, the emission of atomic and molecular helium during the afterglow is more intense than that in the active discharge, while in the He+2.3%H2O mixture, helium emission is only observed during the discharge pulse and the molecular helium emission disappears. In addition, the emissions of OH(A-X) and Hα present similar behavior that increases sharply during the falling edge of the voltage pulse as the electrons cool down rapidly. The gas temperature is set to remain low at 540 K by fitting the OH(A-X) band. A comparative study on the emission of radiative species (He, He2, OH and H) is performed between these two discharge cases to derive their main production mechanisms. In both cases, the dominant primary ion is He+ at the onset of discharges, but their He+ charge transfer processes are quite different. Based on these experimental data and a qualitative discussion on the discharge kinetics, with regard to the present discharge conditions, it is shown that the electron-assisted three-body recombination processes appear to be the significant sources of radiative OH and H species in high-density plasmas.

Numerical thermalization in 2D PIC simulations: Practical estimates for low-temperature plasma simulations

The process of numerical thermalization in particle-in-cell (PIC) simulations has been studied extensively. It is analogous to Coulomb collisions in real plasmas, causing particle velocity distributions (VDFs) to evolve toward a Maxwellian as macroparticles experience polarization drag and resonantly interact with the fluctuation spectrum. This paper presents a practical tutorial on the effects of numerical thermalization in 2D PIC applications. Scenarios of interest include simulations, which must be run for many thousands of plasma periods and contain a population of cold electrons that leave the simulation space very slowly. This is particularly relevant to many low-temperature plasma discharges and materials processing applications. We present numerical drag and diffusion coefficients and their associated timescales for a variety of grid resolutions, discussing the circumstances under which the electron VDF is modified by numerical thermalization. Though the effects described here have been known for many decades, direct comparison of analytically derived, velocity-dependent numerical relaxation timescales to those of other relevant processes has not often been applied in practice due to complications that arise in calculating thermalization rates in 1D simulations. Using these comparisons, we estimate the impact of numerical thermalization in several examples of low-temperature plasma applications including capacitively coupled plasma discharges, inductively coupled plasma discharges, beam plasmas, and hollow cathode discharges. Finally, we discuss possible strategies for mitigating numerical relaxation effects in 2D PIC simulations.

Clinical efficacy of local application of low-temperature plasma at treatment of chronic recurrent aphthous stomatitis

Clinical efficacy of local application of low-temperature plasma at treatment of chronic recurrent aphthous stomatitis

Exploring Factors Influencing the Inhibitory Effect of Volume Dielectric Barrier Discharge on Phytopathogenic Fungi

The application of Low-Temperature Plasmas has shown great potential as an effective and alternative tool for microbial inactivation in recent years. Nevertheless, further investigations are required to fully understand the possible factors influencing these processes. The present study aims to investigate the effectiveness of square wave modulated Volume Dielectric Barrier Discharge on the direct inhibition of conidial germination in five different fungal species, various discharge conditions, and medium composition. The five different fungal species used were Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius, Fusarium graminearum, and Alternaria alternata. On water agar, the inhibition of Botrytis cinerea was influenced by the applied voltage, which mainly reflects the uniformity of the treatment. Under the selected voltage condition, the inhibition increased with treatment duration and decreased with fungal spore complexity. B. cinerea and M. fructicola, with unicellular conidia and low melanin content, showed similar behaviour and high sensitivity to the treatment. F. graminearum and A. alternata, both having multicellular conidia, were more resistant to the plasma treatment and showed different sensitivity likely due to different content in melanin. However, after 1 min of treatment, complete inhibition of conidial germination was achieved for all the tested species. Inhibition of A. carbonarius conidia on different agarized media containing dextrose or malt extract was influenced by the complexity and composition of the medium, being potato dextrose agar that more hindered the plasma efficacy. Each medium exhibited a different electrical response studied by Electrical Impedance Spectroscopy and morphology observed by Scanning Electron Microscopy images. These differences translated into a different response to the applied electrical field, influencing plasma generation and uniformity.

A novel treatment approach for traumatic scalp defects with exposed calvaria denuded of pericranium by combined application of low-temperature plasma and negative pressure wound therapy: A case series.

Traumatic scalp defects with an exposed calvaria denuded of the pericranium are challenging to manage. In such cases, adjunctive therapies, such as milling the outer calvarial cortex and applying negative pressure wound therapy (NPWT), can promote granulation tissue. This case series describes the successful management of traumatic scalp defects after cortical craniectomy using a combination of low-temperature plasma (LTP) and NPWT. This is a retrospective single-surgeon case series. Three patients with traumatic scalp wound defects underwent cortical calvarial bone removal after LTP combined with NPWT. LTP was applied to the diploic space of the calvaria weekly or twice weekly using BioPlasmaJet BPJ1 (BIOPlasma System: Model-BioPlasmaJet System). Subsequently, NPWT was applied with a continuous pressure of 110 mmHg until good granulation tissue formation was achieved for skin graft placement. Two males and one female were included, and the mean follow-up duration was 7 (range 3-12) months. In addition, the average time to achieve good granulation tissue formation was 4 (2-6) weeks; all patients achieved successful split-thickness skin grafting within 3 weeks after placement without signs of calvarial infection. The combination of LTP and NPWT is a safe and effective treatment modality for scalp defects with exposed calvaria denuded of the pericranium resulting from trauma. Combining these two therapies may provide a synergistic effect that enhances granulation tissue formation and prevents local infections without complications.

Tailored design of 2D MOF derived carbon boosting the low temperature plasma catalysis for water treatment: The role of graphitization and hierarchical porous structure

The application of efficient and non-polluting low-temperature plasma technology to address the growing problem of environmental pollution has received increasing attention in recent years. In this study, two-dimensional (2D) Co-ZIF (Co-ZIF-L) derived hollow carbon nanosheets (Co-HCNSs) with high graphitization rate and high porosity were designed. The advantages of structure and composition endow Co-HCNSs-9 with excellent catalytic properties. To verify the effects of graphitization and hollow structure, Co-ZIF-L derived solid carbon nanosheets (SCNSs-9) and Zn-ZIF-L derived hollow carbon nanosheets (Zn-HCNSs-9) were prepared in parallel. In low-temperature plasma applications, the degradation rate of tetracycline (TTCH) was as high as 97% within 30 min, Co-HCNSs-9/dielectric barrier discharge (DBD) system improved the degradation rate of TTCH and the energy efficiency The degradation mechanism of Co-HCNSs-9/DBD was investigated by quenching experiments as a synergistic effect of hydroxyl radicals (OH), singlet oxygen (1O2) and reactive nitrogen species (RNS). In addition, the effects of common anions and natural macromolecular organic compounds in the water column were investigated. Based on 3D fluorescence analysis, liquid chromatography-mass spectrometry and density functional theory calculations, possible degradation pathways of TTCH were proposed. Finally, the safety and environmental friendliness of the system was verified by biological toxicity tests.

Inactivation of Alicyclobacillus contaminans spores by dielectric barrier discharge plasma and its biological mechanism

Over the years, as an emerging technology, cold plasma (CP) has been widely used in the preservation of agricultural products. Alicyclobacillus spp. are spore-forming bacteria and difficult to inactivate. They adversely affect the economic value of agricultural products. Nevertheless, there are still few studies related to the inactivation of spores using CP. Herein, the inactivation effect and mechanism of dielectric barrier discharge plasma (DBDP) on Alicyclobacillus contaminans (A. contaminans) spores in phosphate-buffered saline and clarified apple juice were investigated. Plasma treatment at 75 V for 9 min achieved 99% inactivation of spores with the initial inocula of 7.13 and 5.72-log in PBS and apple juice, respectively. And the cell structure of the spores was severely disrupted leading to the leakage of the entocyte. Moreover, the surface properties of the spores were altered, making the adhesion of the spores to the hydrophobic surfaces and the stability of the bacterial suspension decreased leading to more agglomeration of the spores. Further results confirmed the intracellular homeostasis of the spores was also disrupted. Therefore, the inactivation mechanism of DBDP on spores was revealed from different perspectives, and our discoveries promote the theoretical progress in the use of plasma in food sterilization. Industrial relevanceAs an emerging nonthermal preservation technology, cold plasma has been used in food processing. In this study, we confirmed the feasibility of the inactivation of Alicyclobacillus contaminans spores in apple juice by dielectric barrier discharge plasma (DBDP) and investigated the mechanism of plasma inactivation of spores at the molecular biology level. This paper provides preliminary support for the application of low-temperature plasma in food processing such as apple juice.

Research Progress and Future Trends of Low Temperature Plasma Application in Food Industry: A Review.

Food nutrition, function, sensory quality and safety became major concerns to the food industry. As a novel technology application in food industry, low temperature plasma was commonly used in the sterilization of heat sensitive materials and is now widely used. This review provides a detailed study of the latest advancements and applications of plasma technology in the food industry, especially the sterilization field; influencing factors and the latest research progress in recent years are outlined and upgraded. It explores the parameters that influence its efficiency and effectiveness in the sterilization process. Further research trends include optimizing plasma parameters for different food types, investigating the effects on nutritional quality and sensory attributes, understanding microbial inactivation mechanisms, and developing efficient and scalable plasma-based sterilization systems. Additionally, there is growing interest in assessing the overall quality and safety of processed foods and evaluating the environmental sustainability of plasma technology. The present paper highlights recent developments and provides new perspectives for the application of low temperature plasma in various areas, especially sterilization field of the food industry. Low temperature plasma holds great promise for the food industry's sterilization needs. Further research and technological advancements are required to fully harness its potential and ensure safe implementation across various food sectors.

A double‐mode planar argon plume produced by varying the distance from an atmospheric pressure plasma jet

AbstractAtmospheric pressure planar plumes are desirable for the applications of low temperature plasmas, such as rapid modification of large‐scale surfaces. Up to now, only single‐mode planar plumes with either a streamer mode or a filamentary mode have been reported in the literature. Distinctive from the single‐mode planar plumes, a double‐mode argon planar plume has been generated in this article, which operates in the streamer mode with a larger distance away from a plasma jet and transits to the filamentary mode with decreasing the distance. Discharge characteristics and plasma parameters are compared for the two modes. Results indicate that the streamer mode and the filamentary mode correspond to pulsed and humped discharges respectively. Fast photography reveals that the streamer‐mode plume is composed of stochastically branching streamers, while the filamentary‐mode plume results from a series of moving filaments similar to those in barrier discharge. In contrast to the streamer mode, the filamentary mode has lower excited electron temperature and vibrational temperature, whereas higher electron density and gas temperature. In addition, better hydrophilicity of polyethylene terephthalate surface is achieved in the filamentary mode.

Recognition of Plasma-Treated Rice Based on 3D Deep Residual Network with Attention Mechanism

Low-temperature plasma is a new agricultural green technology, which can improve the yield and quality of rice. How to identify the harvest rice grown by plasma seed treatment plays an important role in the popularization and application of low-temperature plasma in agriculture. This study collected hyperspectral data of harvest rice, including plasma seed treated rice, and constructed a recognition model based on the hyperspectral image (HSI) by 3D ResNet (HSI-3DResNet), which extracts spatial spectral features of HSI data cubes through 3D convolution. In addition, a spectral channels 3D attention module (C3DAM) is proposed, which can extract key features of spectra. Experiments showed that the proposed C3DAM can improve the recognition accuracy of the model to 4.2%, while the size and parameters of the model only increase by 4.1% and 3.8%, respectively. The HSI-3DResNet proposed in this study is superior to other methods with the overall accuracy of 97.47%. At the same time, the algorithm proposed in this paper was also verified on a public dataset.

Low-temperature plasma modification, structural characterization and anti-diabetic activity of an apricot pectic polysaccharide

To fully research the anti-diabetic activity of apricot polysaccharide, low temperature plasma (LTP) was used to modify apricot polysaccharide. The modified polysaccharide was isolated and purified using column chromatography. It was found that LTP modification can significantly improve the α-glucosidase glucosidase inhibition rate of apricot polysaccharides. The isolated fraction FAPP-2D with HG domain showed excellent anti-diabetic activity in insulin resistance model in L6 cell. We found that FAPP-2D increased the ADP/ATP ratio and inhibited PKA phosphorylation, activating the LKB1-AMPK pathway. Moreover, FAPP-2D activated AMPK-PGC1α pathway, which could stimulated mitochondrial production and regulate energy metabolism, promoting GLUT4 protein transport to achieve an anti-diabetic effect. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy data showed that the LTP modification could increase the CH bond content while decreasing the C-O-C/C-O bond content, indicating that LTP destroyed the C-O-C/C-O bond, which enhanced the anti-diabetes activity of the modified apricot pectin polysaccharide. Our findings could pave the way for the molecular exploitation of apricot polysaccharides and the application of low-temperature plasma.

Investigation on optical and electrical properties of soil discharge under pulse voltage

Many researchers have studied the application of low temperature plasma in soil remediation, but most focus on the degradation efficiency of a specific pollutant, and less attention is paid to the development and evolution process of plasma behind the soil remediation. In this paper, the possible mechanism behind soil discharge under pulse voltage is studied from the perspectives of electricity and optics. The electrical and optical analyses show that the soil discharge under pulse voltage mainly exists at the rising stage of pulse voltage, and the existence time is related with the pulse voltage amplitude. At the same time, the relative intensity of active substances (•OH, H, O Ⅱ and N Ⅰ), vibration temperature and rotational temperature are obtained by using the emission spectrum, which demonstrate that high pulse voltage can increase the concentration of active substances, vibration temperature and rotational temperature.

Application of low-temperature plasma for the removal of copper chloride layers on bronze Wares

Archaeological objects based on copper alloys (such as bronze wares) usually suffer from “bronze disease” that results from the existence of CuCl on the surfaces. The surface-coating Cu2(OH)3Cl can release Cl− and lead to further corrosion during the storage procedure. The central aim of the work is the verity the effectiveness of low-temperature radio-frequency (RF) plasma for the removal of CuCl and Cu2(OH)3Cl from the bronze wares. In this work, CuCl and Cu2(OH)3Cl patina were synthesized on copper by a simple solution method. The chemical and aesthetic features before and after plasma treatment were characterized using optical microscopy (OM), SEM-EDS, XRD, and XPS. The results show that Ar-H2 plasma could reduce the CuCl to Cu efficiently, which achieves pleasing esthetics as well as removes the chlorine (Cl atomic ratio decrease from 46.0 to 3.6%). For Cu2(OH)3Cl, the air plasma treatment exhibit better performance compared to the Ar-H2 plasma treatment, judging from the aesthetic effect and the removal effect of chlorine (Cl atomic ratio decrease from 14.8 to 3.3%).

High voltage nanosecond pulse generator based on pseudospark switch and diode opening switch.

With the development of technology, low-temperature plasma plays an increasingly important role in industrial applications. The industrial application of low-temperature plasma has the following requirements for plasma, high electron energy, low macroscopic temperature, and uniformity. Low-temperature plasma driven by nanosecond pulses reflects more significant advantages in these aspects compared to direct current plasma and alternating current plasma. In this paper, a simple topology is proposed, which is based on the pseudospark switch and the diode opening switch. A pulse generator is developed, which can eventually output pulses with an amplitude of 106kV, a rise time of 15.5ns, a pulse width of 46ns, and a maximum repetition rate of 1kHz on a 260Ω resistive load. The pulse generator can successfully drive needle-plate discharge plasma in ambient air. It has excellent parameters, stability, compactness, and a long lifetime. The proposed topology may be helpful for nanosecond pulse generators with amplitude ranging from tens to hundreds of kilovolts, which could be widely used in industry.

Mechanism of low-temperature helical streamer discharge driven by pulsed electromagnetic field

Under the condition of specific pulsed discharge parameters, the discharge mode conversion of the low-temperature plasma jet discharge channel that originally propagates along a straight line will occur, forming a three-dimensional helical plasma channel. Unlike the traditional helical wave discharge, there are no factors such as an external constant magnetic field that destroys the poloidal symmetry of the dielectric tube, and the chiral direction of the helical streamer will change with the discharge parameters. In order to understand in depth the electromagnetic mechanism of the helical structure in the plasma jet, and the source and influencing factors of the poloidal electric field that leads to the helical shape and determines the chirality in this new type of discharge, we analyze the complex characteristics and electromagnetic mechanism of the helical streamer, such as the chiral direction, pitch, branching, by establishing a self-consistent plasma theoretical model. It is found that the phase of the poloidal wave mode has an effect on the chiral selection of the helical streamer, that the electron density has an influence on the pitch of the streamer, and that the repetition frequency has an effect on the bifurcation point. The above discharge characteristics and their influencing factors are of scientific significance in exploring the interaction mechanism of electromagnetic wave and plasma, and also in providing experimental and theoretical support for the chiral application of low-temperature plasma.

Evaluation of the Promotion for Antibacterial Activity on Cibotium barometz J. Smith with Low-Temperature Plasma from Electric Currents and Magnetic Fields

Many studies have been conducted in pursuit of health and safety. This study aims to suggest a preventive and therapeutic plan to address dental caries by confirming the antibacterial effect of Cibotium barometz J. Smith (Cibotium barometz J. S), a natural material, on Streptococcus mutans (S. mutans), a type of bacteria that can cause dental carries, and to maximize the efficiency of antibacterial activity by applying low-temperature plasma from electric currents and magnetic fields. Low-temperature plasma can be applied to living tissue without thermal damage, and the composition of plasma is diverse, so the application field is increasing. Cibotium barometz J. S extract was treated with S. mutans diluted to 1 × 10SUP5/SUP CFUs/mL from low concentration (0.01 mg/mL) to high concentration (45 mg/mL) for 6 and 24 hours. CFUs (colony forming units) were counted for the corresponding time, and lowtemperature plasma was used in combination to maximize antibacterial effect. The higher the concentration of Cibotium barometz J. S extract, the higher the death rate was, and antibacterial activity increased when combined with low-temperature plasma, compared to using Cibotium barometz J. S extract alone. The application of low-temperature plasma improves the penetration of Cibotium barometz J. S extract safely and effectively to suppress the occurrence of dental caries, and has good antibacterial effect. Therefore, low-temperature plasma is considered excellent in promoting oral health.

Plasma medicine: Prospects and experience of application of low-temperature argon plasma in medical rehabilitation

Plasma medicine is a dynamically developing field of science based on the physical and chemical properties of air-plasma flows.
 Low-temperature plasma is a partially ionized gas with a temperature of about 40C, the synergistic interaction of its active substances is a successful method of sterilization, decontamination of wound surfaces, treatment of surgical and burn wounds. Due to the combined action, over the past decades, low-temperature plasma has proven itself in purulent surgery, dermatology, and dentistry, but in addition, it has opened up great prospects in oncology. Possessing the effects of inhibiting inflammatory processes, stimulating regeneration processes, improving microcirculation and tissue metabolism, plasma flows are also used in medical rehabilitation.
 The review considers the possibilities of using low-temperature plasma in various fields of medicine, as well as the effect of plasma flows on basic cellular processes and various forms of cell death. The experience of using low-temperature argon plasma in the complex rehabilitation of patients with malignant neoplasms is presented.
 Literature sources from Russian and foreign databases (Elibrary, PubMed) on the topic of low-temperature plasma application in medical practice were analyzed. The analysis showed that plasma medicine is a rapidly developing modern direction, opening up new opportunities in healthcare.
 Further studies of plasma streams are needed to unlock their full therapeutic potential and fully understand the mechanisms of action.

XIII Scientific Technical Conference on Low Temperature Plasma During the Deposition of Functional Coatings

In the city of Kazan from November 2 to November 4, 2021 on the basis of the Kazan Federal University hosted the XIII Scientific Technical Conference on Low Temperature Plasma during the Deposition of Functional Coatings.One of the main tasks of the conference is to discuss and develop the fundamental principles of plasma deposition of functional coatings. Conference papers were presented in the following areas:- Physics of gas discharge;- Physical processes in low-temperature plasma when applying functional coatings;- Thermodynamic, portable and optical properties of low-temperature plasma in coating processes;- Interaction of plasma and high-energy ion beams with a solid;- Combustion processes and heat and mass transfer in multiphase media;- Dusty plasma;- Plasma chemistry. Electrochemistry;- Diagnostics of low-temperature plasma;- Characteristics of coatings obtained using low-temperature plasma;- Application of ion-plasma coatings.Within the framework of the conference, a school for young scientists is held, lectures by leading scientists and specialists in the field of low-temperature plasma application are held.Gas-discharge plasma is widely used in various fields of science and technology. Plasma is used in industry, medicine, ecology and is the basis of various devices and technologies, for example, it is used in the technology of applying functional coatings.The friendly atmosphere at the XIII Scientific Technical Conference on Low Temperature Plasma during the Deposition of Functional Coatings allowed it to become an excellent platform for the exchange of experience and generation of new ideas in the field of physics and the use of low-temperature plasma.This year, studies of gas-discharge phenomena in electrolytes, studies on the use of ultrasound to obtain metal powder in a plasma discharge electrolyte, calculations of electro-contact firing of steel powders were presented. A series of works is devoted to heat and mass transfer in multiphase media and the study of materials and coatings obtained using low-temperature plasma.List of Organizing Committee, Scientific Committee are available in this Pdf.

The Effects of Storage Temperature, Light Illumination, and Low-Temperature Plasma on Fruit Rot and Change in Quality of Postharvest Gannan Navel Oranges.

Gannan navel orange (Citrus sinensis Osbeck cv. Newhall) is an economically important fruit, but postharvest loss occurs easily during storage. In this study, the effects of different temperatures, light illuminations, and low-temperature plasma treatments on the water loss and quality of the Gannan navel orange were investigated. The fruit began to rot after 90 d of storage at 5 °C and 20-45 d at 26 °C. Navel oranges stored at 26 °C had 7.2-fold and 3.1-fold higher rates of water loss at the early and late storage stages, respectively, as compared with those stored at 5 °C. Storage at 5 °C decreased the contents of total soluble solids at the early storage stage and the contents of titratable acids at the late storage stage, whereas storage at 26 °C decreased the contents of total soluble solids at the late storage stage and the contents of titratable acids at the early storage stage, respectively. Application of low-temperature plasma produced by air ionization for 6 min, or continuous blue or red light illumination significantly inhibited water loss within 7 and 21 d of storage at 22 °C, respectively, but exhibited no significant effect on fruit quality. Furthermore, the low-temperature plasma treatment protected against fruit rot. Thus, treatment with low-temperature plasma followed by storage at a low temperature under continuous red or blue light illumination was of potential value as a green technology for preserving Gannan navel orange during storage.

Influence of air and water vapor on EEDF, plasma parameters, and the main RONS in atmospheric pressure low temperature helium plasmas: Global model approach

A zero-dimensional global model is developed with an aim to study the influence of air and water vapor on an electron energy distribution function, electron density, and temperature as well as on the chemical composition of atmospheric pressure helium plasmas, with special focus on the main reactive oxygen and nitrogen species important for applications of low temperature plasmas. The main channels for the production and consumption of electrons and electron energy gain and loss are examined by a global model based on a parametric study with variations of the mole fractions of air and water vapor. The calculations are done for 100, 1000, and 10 000 ppm of air in plasma, and for each of these values, the content of water vapor is taken to be 100, 1000, 2000, …, to 10 000 ppm. The variations of the most important production and consumption processes for reactive oxygen and nitrogen species are analyzed in detail. According to the results presented in this paper, water vapor highly contributes to electronegativity of the plasma through pronounced attachment of electrons, which then leads to an increase in electron temperature. For high water vapor content, vibrational excitations of water molecules are one of the main electron energy loss processes, leading to a further effect on the plasma composition. Water decreases concentrations of atomic oxygen, nitrogen, and ozone, while there is an increase in nitrogen oxide, OH, H2O2, and HO2 concentrations. Cross-sectional data for electron scattering on ground and excited state neutrals are mainly taken from the Quantemol-DB database.