Corona Discharge Plasma Research Articles

Current, thrust, and power of a corona discharge plasma thruster at tropospheric altitude

Abstract Recent developments in electro-aerodynamics (EAD) thrusters that use plasma have demonstrated their abilities for aircraft propulsion, at least for low-velocity drones. Further improvements in the technology bring EAD propulsion closer to full-scale applications. However, certain doubts still exist concerning their behavior in different atmospheric conditions. The study focuses on the effects of altitude on the propulsive performance of a corona discharge thruster in the troposphere. A thruster is placed in a climatic chamber that can vary the temperature and pressure independently, and force and current measurements provide the thrust generation and power consumption of the thruster. First, tests under varying pressure between 500 and 1000 hPa were performed at room temperature. As expected, at constant voltage, they highlight that the power increases almost linearly when the pressure decreases. Conversely, they found that the thrust decreases with pressure at a constant current. The combined effects result in a loss of effectiveness (i.e. thrust-to-power ratio) when the pressure reduces. Yet, a plateau of maximum effectiveness is achieved between 800 and 1000 hPa. Secondly, the temperature was varied between -20 and +30°C at ground pressure. No significant effect was captured concerning the current and power, and a weak decrease in thrust was measured at higher temperatures. Finally, altitudes between 0 and 6 km by combining pressure and temperature modifications were simulated. Mostly led by the pressure drop, the power decreases linearly when the altitude increases, but the thrust decreases to a plateau between 3 and 6 km. Hence, the effectiveness also decreases with altitude down to a stagnation between 3 and 6 km. The coupled decreases in drag and thrust with altitude engender a small decrease in the maximum achievable flight velocity of the thruster down to a plateau over 3 km.

Response surface optimisation for corona discharge treatment of nicosulfuron in water

ABSTRACT Sulfonylurea herbicides are the most widely used herbicides in the world, which are widely used in the prevention and control of weeds in rice, wheat, soybean and other fields. Long-term application will cause environmental pollution, and the use of plasma technology to degrade herbicides in water is expected to be an effective method to restore pollution. In this experiment, corona discharge plasma was used to treat nicosulfuron in water, and the response surface method was used to optimise the operating conditions of the single system of corona discharge treatment of nicosulfuron and the synergistic system of corona discharge treatment of nicosulfuron with the addition of persulfate. The results showed that the degradation rate of nicosulfuron was 75.08% after 10 min under the optimum operating condition of single system. Under the optimum operating conditions, the degradation rate of nicosulfuron after 10 min was 100%. The R2 and P values of the two system models were both greater than 9.3 and less than 0.01, and the reliability of the simulated degradation rate data was verified by experiments, which provided basic data for the future research on the use of low temperature plasma to degrade herbicides.

The Influence of Additive Migration on the Surface Properties of Polypropylene-Based Films during Modification in Low-Temperature Corona Discharge Plasma

The Influence of Additive Migration on the Surface Properties of Polypropylene-Based Films during Modification in Low-Temperature Corona Discharge Plasma

Efficacy of Atmospheric Non‐thermal Plasma Corona Discharge Under Dry and Wet Conditions on Decontamination of Food Packaging Film Surfaces

ABSTRACTFood packaging materials must be sterilized to prevent cross‐contamination of the product. Non‐thermal plasma (NTP) corona discharge can be an effective alternative sterilization method for packaging films. The inactivation efficiency atmospheric NTP corona discharge under dry and wet conditions against vegetative cells of Escherichia coli, Staphylococcus aureus and Bacillus subtilis, spores of B. subtilis and Clostridium sporogenes and fungal spores of Candida albicans, Penicillium expansum and Aspergillus niger on polymeric packaging films were studied. The maximum inactivation of these microorganisms was 5.58, 0.54, 1.51, 1.06, 2.47, 1.73, 2.80, 3.20 and 3.50 log, respectively. Microbial inactivation by the treatments was greatly enhanced under wet conditions. Gram‐negative bacteria were found to be more sensitive to NTP, but spores were more resistant than vegetative bacterial cells. Although fungi were less susceptible than bacteria in dry treatments, they became more sensitive than the Gram‐positive bacteria in wet treatments. Overall, plasma treatments under wet conditions achieved higher microbial inactivation and would be favourable over the dry treatment.

Numerical Simulation of Corona Discharge Plasma Affecting the Surface Behavior of Polymer Insulators

Corona discharge is a significant problem in the operation of high-voltage transmission and distribution systems, particularly for polymer insulators. Numerical simulation has become an effective tool for investigating the underlying physical mechanisms and optimizing the design of insulators. In this paper, we present a two-dimensional numerical simulation study on corona discharge plasma affecting the surface behavior of polymer insulators. The simulation was performed with the Comsol Multiphysic software and is based on the finite element method and the fluid plasma model, which considers ionization, recombination, and the transport of plasma species. The numerical results are analyzed to study the spatial and temporal characteristics of the corona discharge and its effect on the surface behavior of polymer insulators. The results show that the electric field is affected not only by the volume charge density but also by the surface charge density, which in turn depends on the densities of the charge carriers migrating on the insulator surface. However, the electric field drops drastically when one or two grading rings are installed. But one grading ring is not enough to limit the discharge.

Innovative plasma treatment of orange juice to improve bioactive concentration: The effects of various parameters using response surface analysis.

Orange juice is a highly nutritious beverage. Traditional pasteurization methods cause nutrient loss and taste changes. Plasma treatment (PT) is an emerging method with a high sterilization rate. This study investigated the effects of corona discharge plasma on the sterilization of orange juice by changes in color difference, total phenol content, and pH value. Single-factor experiments revealed that higher voltage (40kV) and longer sterilization time (25min) had better sterilization effects. Response surface analysis indicated that frequency had the greatest impact on sterilization rates, and the optimal sterilization conditions were a voltage of 44.75kV, a frequency of 9.46kHz, and a sterilization time of 25min. Under these conditions, the sterilization rate reached 97.9%, meeting the national standard of 104 colony-forming units/mL (GB7101-2022). Compared to untreated juices, the color difference value was 16.32, the pH value decreased by 0.12, and the total phenol content increased by 0.669mg/mL. However, the evaporation of water plays an important role in increasing the total phenol co. Moreover, the comparative analysis showed that PT was comparable to pasteurization in terms of sterilization effects, flavor preservation, and the concentration of bioactive components. This study provides a theoretical basis for industrial applications of PT.

Corona discharge plasma-excited activation of MnZrLaCe/γ-Al2O3 catalyst for simultaneous degradation of meta-xylene and ethyl acetate: Effects and mechanism

The effects for the simultaneous degradation of meta-xylene (MX) and ethyl acetate (EA) by corona discharge plasma (CDP) combined with MnZrLaCe/γ-Al2O3 were investigated. The MnZrLaCe/γ-Al2O3 were characterized by SEM-EDS, XRD, BET, XPS, FT-IR and O2-TPD. The simultaneous degradation mechanism of the CDP combined catalyst for the mixed VOCs was discussed. Compared with degradation the single component, the degradation efficiency of MX and EA simultaneously is greatly higher than that of the CDP alone. The degradation efficiency of EA, MX and the mixture by the CDP combined with catalyst is up to 93.6 %, 94.5 % and 83.5 % at supply voltage 40 kV, and is 61.2 %, 43.3 % and 33.4 % higher than that of the NTP alone, respectively. The simultaneous degradation efficiency of MA and EA mixed pollutants is significantly improved after the addition of catalysts at the same supply voltage. The EY of all CDP combined with catalysis generally have a down ward trend with increasing of the supply voltage. The best EY for degrading MA and EA mixed pollutants simultaneously by the CDP combined with MnZrLaCe/γ-Al2O3 are up to 7.45 g/kWh at supply voltage 24 kV. The O3 concentration in the outlet gas of the CDP reactor is relatively low, and the NOx in the outlet gas is essentially absent. The main intermediate products of simultaneous degradation MX and EA by the CDP combined with MnZrLaCe/γ-Al2O3 are n-heptane, toluene and paraxylene, etc. Finally, the degradation mechanism for the MX and EA simultaneously by the CDP over the MnZrLaCe/γ-Al2O3 catalyst are proposed.

Design of double Z-scheme Ag–Ag3O4/CuO–CuFe2O4 magnetic nanophotocatalyst via starch-templated microwave-combustion hybrid precipitation method and modified with corona-plasma: Remediation of dye contaminants

Herein, the novel double Z-scheme Ag–Ag3O4/CuO–CuFe2O4 magnetic nanophotocatalyst with nanosphere-on-nanosheet-like morphology was synthesized via the corona-plasma-assisted starch-templated microwave-combustion-precipitation method to remove the dye pollutants. The CuO–CuFe2O4 meso/macroporous nanophotocatalyst was synthesized using a one-pot-stage combustion-microwave process with/without starch as a hard-template. Subsequently, surface modification was carried out by DC corona-plasma discharge technology at various voltages, namely 500, 1000 and 1500 V. Then, the Ag3O4 photocatalyst was deposited on the CuO–CuFe2O4 fabricated with starch-hard-template and treated with 1000 V corona-plasma (denoted as: Ag–Ag3O4/CuO–CuFe2O4 (Starch) 1000 P). The properties of the synthesized nanophotocatalysts were analyzed using various techniques, including X-ray diffraction (XRD), Diffuse reflectance spectroscopy (DRS), Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller and Barrett-Joyner-Halenda (BET-BJH), Vibrating Sample Manetometer (VSM), and Photoluminescence (PL). The XRD analysis corroborated the presence of CuO, CuFe2O4 and Ag3O4 in the structure of all samples. The BET-BJH analysis indicates that the specific surface area of the Ag–Ag3O4/CuO–CuFe2O4 (Starch) 1000 P nanophotocatalyst as the best sample is 2 m2/g, higher than other samples. Additionally, the DRS analysis revealed that the band gap of the Ag–Ag3O4/CuO–CuFe2O4 (Starch) 1000 P nanophotocatalyst is about 1.68 eV with the surface plasmon resonance. The performance of the ternary heterostructured Ag–Ag3O4/CuO–CuFe2O4 (Starch) 1000 P nanophotocatalyst was 96.2% and 89.1% in the degradation of the crystal violet (10 mg/L) and acid orange 7 (10 mg/L), respectively, proving its outstanding degradation capacity.

Corona discharge plasma for green de-inking of inkjet printer ink

This work features a new corona discharge plasma technology for de-inking yellow, blue, and red colors on various papers. This work was developed to minimize the chemical and environmental impacts of de-inking processes. A nonchemical contribution, operating at room temperature and atmospheric pressure, reduces the environmental impact of the process. The deinkability factor (DEMLab) values for all papers are determined with the optimal assessment results provided by a 36-mm variation gap at 2-min (blue) and 10-min (yellow and red) plasma exposure times, followed by applied voltages of 20 kV (yellow), 16 kV (blue), and 20 kV (red). The corona discharge plasma led to 48.58% (yellow printed paper), 64.11% (blue printed paper), and 41.11% (red printed paper) deinkability without altering the physical properties of the paper itself. The change in the tensile strength for the plasma-exposed paper was relatively little, less than 10%, compared to that of common recycling. The tensile strength of the untreated white paper was 5065 ± 487.44 N/mm2, and that of the plasma-treated printed paper was 4593 ± 248.47 N/mm2. It appears that there is little impact on the physicochemical properties of paper induced by the corona plasma treatment during the de-inking process.

Effect of Corona Discharge Plasma Radiation on the Viability of True Shallot Seeds (Allium cepa L. var. aggregatum)

TSS (True Shallot Seed) need to be developed to address the quality and quality of shallot seeds. The seeds, however, still has constraints on its viability and germination. The objective of this study was to investigate the effect of corona discharge plasma radiation on the viability of true shallot seeds. The research was conducted in March - April 2023 at the Plasma Laboratory, Faculty of Science and Mathematics, Diponegoro University, and the germination test experiments at the the Agricultural Technology Research and Assessment Installation (IP2TP Ungaran). The experiment was designed completely randomized with 6 treatments of radiation time consisting of P0 (without radiation), P1 (5 min), P2 (10 min), P3 (15 min), P4 (20 min), and P5 (25 min). All treatments were carried out with 5 replications. The collected data were processed using ANOVA and then continued with the DMRT test. The results showed that the corona plasma radiation treatment for 15-25 min affected the parameters of germination, germination rate, seed growth rate, vigor index, seed uniformity, and sprout length. Keywords: Plasm, Radiation, Shallots, TSS.

Effects of corona discharge plasma pretreatment on the drying kinetics and quality attributes of lily (Lilium davidii var. unicolor) bulbs

The objective of this study was to examine the impact of corona discharge plasma (CDP) treatments of different durations (1, 3, 5, and 10 min) on the drying kinetics and quality attributes of lilies, including color, enzyme activities, total phenols content (TPC), and antioxidant activity. The microstructure of lilies under different CDP conditions were also investigated. As a result, all CDP treatments enhanced the drying rate relative to untreated lilies, and the shortest drying time of 7 h was obtained at CDP-3 minute samples. CDP treatment led to a higher retention in the TPC of dried lilies. Microstructural analysis revealed the formation of irregular micropores on the surface of the lilies after CDP treatment, which was closely associated with the accelerated drying rate and improved bioactive substances of the dried product. In conclusion, CDP has emerged as a novel and beneficial pretreatment technique that accelerates the drying process and enhances the nutritional qualities of dried lilies.

Separation of water-oil emulsion by polyamide membranes treated with corona plasma

Studies were carried out on the separation of the water-oil emulsion by polyamide membranes with a pore size of 0.2 μm treated with corona discharge plasma at a voltage of 5–25 kV and a time of 1–5 minutes. An increase in the productivity and efficiency of the separation of the water-oil emulsion by corona-treated polyamide membranes was revealed. Increase of roughness and change of chemical structure of modified membranes are shown.

Seed priming with corona discharge plasma modified growth performance, improved metabolism, and elicited production of tropane alkaloids in Datura inoxia seedlings; plasma technology for application in plant in‐vitro cultures

AbstractThis study monitored the growth, biochemical, and developmental responses of Datura seedlings to the cold plasma. The effectiveness of different methods was explored to break seed dormancy. Germinating seeds were exposed to corona discharge plasma for different durations, including 0, 60, 120, 180, and 300 s. A procedure consisting of illumination with a red light (20 min), soaking in water (4°C for 48 h), and removing a part of Testa was the best method for breaking seed dormancy. The plasma treatments of 60, 120, and 180 s improved the plant growth performance, while this trait was declined in response to the plasma treatment of 300 s. The proline concentrations in both root and leaves displayed a linear significant upward trend in response to the plasma treatments. The plasma for 180 s was the most effective method to increase tropane alkaloids. With increasing the exposure time from 60 to 300 s, the leaf soluble phenols were linearly enhanced. The plasma application for 60, 120, and 180 s significantly augmented total protein concentration, while the exposure of seeds for 300 s significantly diminished it. The highest amounts of photosynthetic pigments (chlorophylls and carotenoids) were recorded in the seedlings treated with plasma for 120 and 180 s. The activities of enzymatic antioxidants (catalase and peroxidase) showed a similar upward trend to that of proline. The plasma priming also improved the phenylalanine ammonia‐lyase activity (a secondary metabolism index). Further investigations are needed to optimize plasma parameters and understand the involved mechanisms to maximize its benefits while minimizing potential risks.

Effect of high voltage discharge on germination characteristics of vetch seeds at high altitude

High-voltage electrostatic fields and low-temperature plasma technology at atmospheric pressure have an important impact on biological growth promotion. Therefore, a multi-needle-column-plate corona plasma generator is proposed in this paper. The negative corona voltammetry characteristics of multi-needle-plate electrodes and multi-needle-column-plate electrodes with different electrode spacing are investigated experimentally, and the electric field distribution of the device is simulated. The device was also applied to vetch seeds at high altitudes to investigate the effect of discharge on germination and root length. The results show that the introduction of column electrodes can effectively improve the electric field distribution of the device so that the device can provide two modes of high voltage electrostatic field and corona plasma field, and ensure the uniform treatment of seeds when the electrode spacing is 3 cm. The treatment of this device accelerates seed germination and promotes root growth, and is more effective under the combined influence of higher electric field strength, ionic wind generated by the discharge, and the active species than a single factor with a lower electric field, as well as shortening the duration of action. The high voltage electrostatic fields at −3 kV, −6 kV, and −9 kV and the corona discharge plasma fields at −12 kV, −15 kV, and −18 kV can effectively accelerate the germination of vetch seeds as well as promote the root growth under the treatment time of 10 min, 20 min, and 30 min. The optimal conditions were −9 kV for 30 min and −15 kV for 10 min, respectively.

Separation of Oil-in-Water Emulsion by Polyamide Membranes Treated with Corona Discharge Plasma

Separation of Oil-in-Water Emulsion by Polyamide Membranes Treated with Corona Discharge Plasma

TEM and zeta potential titration as suitable techniques for investigating the joining of modified ceramic surfaces

Transmission Electron Microscopy (TEM-EDS) and Zeta potential titration of ceramic surfaces allowed researchers to go inside their adhesion mechanism when joined with an adhesive. The case study concerned the plasma Corona treatment to improve the joint strength between SiC surfaces joined with an epoxy adhesive. The formidable mechanical and chemical properties inherent to silicon carbide pose challenges in applying conventional methods like mechanical machining and wet etching for surface texturing. Exploring alternative strategies, plasma Corona treatment which is an Atmospheric Pressure Plasmas (APPs) process emerges as a potential solution. The mechanism of chemical interaction and mechanical interlocking between plasma-treated surfaces and the epoxy adhesive used for the joining was never explored in detail and proven. The presence of layers with different crystallographic natures and chemical compositions was assessed by TEM-EDS: an amorphous silica layer was produced by the corona activation treatment and it created a mechanical anchoring system when penetrated by the adhesive. The zeta potential titration as a function of pH evidenced that untreated SiC had a surface with amphoteric functional groups, while the Corona treatment induced the formation of surface functional groups (OH) with a strong acidic behavior on SiC. The investigated epoxy adhesive exposed a prevalence of basic amino groups. Zeta potential titration curves highlighted the chemical interaction between the treated SiC surfaces and the epoxy adhesive: the large electrostatic attraction between the OH groups of the treated SiC and the amino groups of the epoxy adhesive had a role in the mechanical strength of the joining. TEM and Zeta potential titration can be proposed as suitable techniques to evaluate the effectiveness of the plasma corona discharge system in modifying the surface of SiC and to solidify its standing in comparison to other established surface modification techniques to improve SiC-based joints.

The Knife-Plane Configuration Model of CCP equipment from plasma corona discharge case

This research discusses the concept of analytical calculations of current-voltage (I-V) characteristics in the case of corona discharges using an asymmetric electrode model (with a DC source), which is often called capacitively coupled plasma (CCP) equipment. This CCP equipment, which is almost similar in shape to capacitor equipment in conventional electrical equipment, has the characteristic of having an active electrode in an upright position above the position of a passive electrode (in a lying position) in the air. Another characteristic is that the lowest end of the active electrode has a sharp surface so that a large corona current flows out of the sharp surface towards the passive electrode. The (I-V) characteristic calculation method can be calculated using a geometric concept (based on the sharp surface at the tip of the active electrode) using a modified capacitance concept. For the case of an asymmetric model with an arrangement of active and passive electrodes perpendicular to each other, the capacitance calculation can use the knife-plane electrode configuration model.

Seed Vigor of Soybean Treated by Corona Discharge Plasma

There is a huge gap between the output and demand of soybean in China. How to improve the seed vigor of soybean has always been a research focus. Low temperature plasma (LTP) is a new green technology, which is widely used in crop seed treatment. Corona plasma is a typical discharge mode of plasma, which can affect the vigor of seeds. The effect of different discharge power on the soybean seed vigor by plasma treatment was experimentally investigated. Plasma discharge characteristic wavelength and spatial distribution were analysed. It shows that the corona discharge spectrum mainly exhibits the strong ultraviolet radiation and 90% of the spectral intensity focused in the center of discharge region. Water absorption and germination index of seeds and the fresh weight of seedlings were used to characterize the specific effects caused by different plasma powers. The results show that plasma treatment has a significant effect on the early stage of germination and can significantly affect the soybean seed vigor and growth. Overdose treatment will cause inhibiting effect. This study provides an experimental basis for the practical agriculture application of corona plasma seed treatment.

Microanalysis of Active Nitrogen Oxides (RONS) Generation Characteristics during DC Negative Corona Discharge at a Needle-Plate Electrode

The DC negative corona of needle-plate electrodes can generate atmospheric pressure low-temperature plasma active particles, which have important effects on biological mutagenesis. The DC negative corona discharge of an air needle-plate electrode with effective consideration of NOx particles was simulated and the Trichel pulse current was obtained, focusing on the development of particles and the distribution of active nitrogen oxides (RONS) at four moments in the pulse process. The simulation results indicate that the positive ions (N2+ and O2+) and negative ions (O− and O2−) were closely related to the current changes, and the negative ions (O− and O2−) presented a typical stratification phenomenon. RONS (H2O2, O3, and NO) were approximately uniformly distributed above the level of the plate electrode at the same instant, with H2O2 and O3 except for the area below the needle tip. They trended to a cumulative increase in concentration with time. This study provides a theoretical basis for corona discharge plasma seed treatment technology.

Investigation of silver nanoparticle synthesis with various nonthermal plasma reactor configurations

In this work is investigated the effect of nonthermal plasma reactor configurations on the synthesis of silver nanoparticle (AgNP) comparing three reactor configurations: (i) coaxial dielectric barrier discharge (DBD), (ii) like-free ground DBD, and (iii) corona plasma discharge. To make the AgNP synthesis cost-effective and eco-friendly, no reducing agent was used and to get stable particles, instead inexpensive sucrose was used as capping agent. The formation and stability of AgNP were verified using ultraviolet–visible (UV–Vis) spectroscopy and energy dispersive spectroscopy (EDS). The concentration and stability of AgNP were found to be dependent on various process parameters, with the optimal conditions of applied voltage, gas flow rate, treatment time, nozzle distance, silver nitrate concentration and sucrose concentration determined at 12 kV, 1.5 L/min, 180 s, 1.0 cm, 0.5 mM, and 20 mM, respectively. The surface morphology and particle size distribution (PSD) obtained with transmission electron microscopy (TEM) showed that the nanoparticle (NP) synthesized by coaxial DBD and corona plasma were spherical in shape with a wide PSD, and their average size was 6.2 nm and 9.6 nm, respectively. On the other hand, those NP synthesized by like-free ground DBD were mostly spherical, along with a few hexagon and triangular shapes. With like-free ground DBD, the PSD was found to be significantly narrower, and the average particle size was 20 nm which is bigger compared to NP synthesized by coaxial DBD and corona plasma. Better performance of AgNP synthesis by the like-free ground DBD is most likely due to higher energy delivery capacity.