Influence Of Non-thermal Plasma Research Articles

Influence of non-thermal plasma and electric field on non-premixed methane flame

Non-thermal plasma possesses several distinctive features such as low energy consumption, strong selectivity, and high activity. Consequently, it holds significant promise for applications in combustion control. Given the strong interdependence of its function with combustion physics and chemical processes, it is imperative to gain a comprehensive understanding of its underlying mechanism from various perspectives. Therefore, this paper aims to investigate the effects of the inherent electromagnetic properties of non-thermal plasma and electric field on methane combustion. Specifically, the focus is on the effects of electric field-driven ionic wind and electric field-enhanced chemical kinetics. Firstly, a design for a coaxial micro-tube burner was developed. By employing a method that involves the continuous modulation of the loading electric field and the utilization of PIV detection, this study aimed to observe the combustion characteristics of methane diffuse and lift-off flames. Additionally, the research sought to determine the variation patterns of the critical de-fire rate and combustion stability. The combustion velocity of a methane laminar flame was measured using the heat flux method, and the impact of an electric field on the flame velocity was determined. The main findings of this study reveal that the electric field and discharge current field play significant roles in ensuring combustion stability. Additionally, it is observed that ionic winds, acting as carriers for flame chemical reactions, and the chemical kinetic effects of non-thermal plasmas contribute positively to flame stability. Furthermore, both AC and DC electric fields generate an adsorption volume force on the surface of the flame.

Influence of Non-Thermal Plasma on the Quality and Nutritional Content of Palm Dates

In this work, the surface dielectric barrier discharge (SDBD) plasma treatment was used to sterilize the palm date fruits. N2SPS, N2FNS, and hydroxyl radical have emerged in the emission spectrum of the plasma from SDBD. The effects of SDBD plasma on A. niger that was extracted from palm date varieties were investigated. After 15 days of incubation, the reduction of A. niger at a 3 min exposure time was 4 log. The total phenolic content of the Ajwa variety after SDBD plasma treatment has been documented as the highest value among the other varieties; it was 1.65-fold of the untreated one. The treated Ajwa variety using SDBD plasma has recorded the highest increase in antioxidant activity; it was increased to 67.69% compared to the control one. After SDBD plasma treatment, the HMF was not detected in the Maghol variety. According to the PCA model, the first two PCs demonstrated strong positive correlations with most of the examined variables and demonstrated a strong positive correlation between these variables when assessed in both untreated and treated with SDBD plasma of palm date types in this stud.

Influence of Non-Thermal Plasma (DBD) On Infertility Male Semen with Low Sperm Motility and Dna Damage

Non-thermal plasma(Dielectric barrier discharge) has many uses including living tissue sterilization, inactivation of the bacteria, excimer formation, angiogenesis, and surface treatment. This research aim is to use cold plasma as a tool to search the effect of the dielectric barrier discharge system at room temperature on human sperm motility and DNA integrity. This work was performed on 60 human semen samples suffering from low motility; each sample was prepared by centrifugation method, then each semen sample was divided into two sections, the first section is before significant exposure to the plasma system (DBD) and the second section is after treatment with the DBD system at ambient temperature. Before and after exposure to non-thermal Plasma (DBD), DNA integrity and sperm motility were assessed, patients suffered from asthenospermia has a high level of DNA fragmentation than fertile male, ( 24.16±4.14) p<0.001 for untreated and after treatment the semen slide with dielectric barrier discharge the percentage decreases to (9.16±1.76) p>0.006, and the comet slide was (35.44±4.15) then the percentage decline to (19.86 ±2.44) these results have shown that cold plasma improves sperm motility and decreases from DNA damage in patients with medium and high level of DNA damage.

Inactivation of viruses using nonthermal plasma in viral suspensions and foodstuff: A short review of recent studies

AbstractThis review tries to introduce the novel and promising technology of the nonthermal plasma against different viruses and virus surrogates, which can trigger food infections and gastroenteritis. It has been reported that the noroviruses are responsible for 21 million cases of gastrointestinal illness annually just in the United States. The article is divided into the introduction for nonthermal plasma, its antiviral mechanism, and the most effective parameters on its antiviral functionality. This technology offers many advantages, including simple in designing, leaving no toxic residues, fast processing, and no thermal degradation of samples. According to the accomplished studies, the exposure distance, processing time, and generated amount of reactive species, particularly singlet oxygen are the main parameters affecting the performance of nonthermal plasma against food viruses. Especially, the capsid and genome of viruses seem to be under influence of nonthermal plasma. Deformation of the capsid envelope through oxidation and damage to the sugar phosphate backbone of viral RNA and DNA are considered the most important factors of reactive species generated by nonthermal plasma on viruses.

Plasma-assisted catalytic reduction of SO2 to elemental sulfur: Influence of nonthermal plasma and temperature on iron sulfide catalyst

Herein, we report on low-temperature sulfur dioxide (SO2) reduction to elemental sulfur via the coupling of nonthermal plasma (NTP) with supported transition metal sulfide catalysts in a dielectric barrier discharge (DBD) reactor. The transition metals include Mo, Fe, Co, Ni, Cu, and Zn. Combining NTP with supported metal sulfide catalysts significantly promotes low-temperature reduction of SO2 by 148–200%, with over 98% selectivity to elemental sulfur. Over FeS2/Al2O3 catalyst at low temperatures (<250 °C), temperature does not influence SO2 conversion in the plasma catalytic process, whereas at higher temperatures, the reaction follows a similar trend as thermal catalysis. Strong synergistic effects are attained, as the sulfur yield is about 47–82% higher than the sum of the yield when using DBD-plasma and thermal catalysis separately. The physico−chemical properties of fresh and spent FeS2/Al2O3 catalysts after thermal and plasma reactions are evaluated by N2 physisorption, FESEM, XPS, XRD, HRTEM, STEM/EDS, and EELS to understand plasma and thermal effects on the catalyst. Our investigations reveal that running the reaction under plasma preserves the surface FeS2 active phase, preventing its oxidation that otherwise occurs in the thermal catalysis process. Furthermore, plasma inhibits the thermal agglomeration of iron sulfide nanoparticles under reaction conditions.

Combination of non-thermal plasma and subsequent antibiotic treatment for biofilm re-development prevention.

The influence of non-thermal plasma (NTP) treatment on the prevention of antibiotic resistance of microbial biofilms was studied. Staphylococcus epidermidis and Escherichia coli bacteria and a yeast Candida albicans, grown on the surface of Ti-6Al-4V alloy used in the manufacture of prosthetic implants, were employed. Their biofilms were exposed to NTP produced by DC cometary discharge and subsequently treated with antibiotics commonly used for the treatment of infections caused by them: erythromycin (ERY), polymyxin B (PMB), or amphotericin B (AMB), respectively. All biofilms displayed significant reduction of their metabolic activity after NTP exposure, the most sensitive was S. epidermidis. The subsequent action of antibiotics caused significant decrease in the metabolic activity of S. epidermidis and E. coli, but not C. albicans, although the area covered by biofilm decreased in all cases. The combined effect of NTP with antibiotics was thus proved to be a promising strategy in bacterial pathogen treatment.

Investigation on the influence of non-thermal plasma on reaction degree of wood gasification in a drop tube reactor

The influence of non-thermal plasma (NTP) on entrained-flow wood gasification at atmospheric pressure was investigated in experiments performed at a drop tube reactor with an inner diameter of 0.1 m. Three particle size categories covering diameters between 125 and 700 µm were used for testing. NTP and thermal gasification were compared applying similar experimental conditions in order to study the contribution of radicals, excited species, and charged particles to the gasification reaction. In case of NTP gasification about 1 kW of electric power was supplied to the preheated steam, whereas in case of thermal gasification the preheated steam was superheated applying about the same heat rate. Due to thermalization the temperature flow-down of the NTP zone approached the temperature after thermal superheating. The syngas-based carbon conversion degree was calculated from the ratio of the carbon content of the gaseous products (CO, CO2 and CH4) to that one of the original feedstock. Results show that NTP enhances syngas production for at least 20% and carbon conversion for 27% compared to thermal gasification. Kinetic rate coefficients for syngas formation as a function of temperature were obtained by fitting the syngas based carbon conversion degree assuming a first order reaction and temperature dependency described by the Arrhenius equation. For NTP gasification reaction rate coefficients increased by 33% as compared to thermal gasification were achieved.

Stimulation of the Germination and Early Growth of Tomato Seeds by Non-thermal Plasma

The influence of non-thermal plasma on tomato seeds has been investigated using a fluidized bed dielectric barrier discharge generated in air. It was found that plasma-treated seeds germinate faster than untreated ones. Plasma slightly enhanced germination rate and considerably influenced growth parameters. Seedling length and weight are significantly higher than those of untreated seeds. The influence of plasma exposure is more visible on the plant roots, which are substantially longer and more branched. An increase in weight of 20–40% was observed for the plants grown from treated seeds as compared to the control ones. The best results are obtained for relatively short plasma exposure, while too long treatment appears to be detrimental to the seeds.

Influence of non-thermal plasma on structural and electrical properties of globular and nanostructured conductive polymer polypyrrole in water suspension

Non-thermal plasma has proved its benefits in medicine, plasma assisted polymerization, food industry and many other fields. Even though, the ability of non-thermal plasma to modify surface properties of various materials is generally known, only limited attention has been given to exploitations of this treatment on conductive polymers. Here, we show study of non-thermal plasma treatment on properties of globular and nanostructured polypyrrole in the distilled water. We observe that plasma presence over the suspension level doesn’t change morphology of the polymer (shape), but significantly influences its elemental composition and physical properties. After 60 min of treatment, the relative concentration of chloride counter ions decreased approximately 3 and 4 times for nanostructured and globular form, respectively and concentration of oxygen increased approximately 3 times for both forms. Simultaneously, conductivity decrease (14 times for globular and 2 times for nanostructured one) and changes in zeta potential characteristics of both samples were observed. The modification evolution was dominated by multi-exponential function with time constants having values approximately 1 and 10 min for both samples. It is expected that these time constants are related to two modification processes connected to direct presence of the spark and to long-lived species generated by the plasma.

Micro-structural and components evolution mechanism of particular matter from diesel engines with non-thermal plasma technology

The present study is about the influence of non-thermal plasma (NTP) technology on soot emissions and physico-chemical properties (morphology, particle size, chemical composition and ignition temperature) of diesel PM. Experiments have been carried out using a small direct injection diesel engine with NTP technology based on a bench test. The physico-chemical properties of PM samples were detected by GC–MS, SEM, EDX, and TGA. PM samples after NTP treatment consisted of mainly hydrocarbons with less than 18 carbon atoms and few hydrocarbons with higher than 20 carbon atoms. Analysis by SEM and EDX showed that the agglomeration degree and the mean spherule diameters were markedly reduced by NTP oxidation. TGA showed that the ending combustion temperatures of PM samples in oxygen environment were 670.03 °C and 550.54 °C before and after NTP treatment, respectively. The mean temperature difference was nearly 120 °C, which indicated that NTP technology could effectively reduce the burning combustion temperature of diesel PM emissions.

Non-thermal Plasma Activates Human Keratinocytes by Stimulation of Antioxidant and Phase II Pathways

Non-thermal atmospheric pressure plasma provides a novel therapeutic opportunity to control redox-based processes, e.g. wound healing, cancer, and inflammatory diseases. By spatial and time-resolved delivery of reactive oxygen and nitrogen species, it allows stimulation or inhibition of cellular processes in biological systems. Our data show that both gene and protein expression is highly affected by non-thermal plasma. Nuclear factor erythroid-related factor 2 (NRF2) and phase II enzyme pathway components were found to act as key controllers orchestrating the cellular response in keratinocytes. Additionally, glutathione metabolism, which is a marker for NRF2-related signaling events, was affected. Among the most robustly increased genes and proteins, heme oxygenase 1, NADPH-quinone oxidoreductase 1, and growth factors were found. The roles of NRF2 targets, investigated by siRNA silencing, revealed that NRF2 acts as an important switch for sensing oxidative stress events. Moreover, the influence of non-thermal plasma on the NRF2 pathway prepares cells against exogenic noxae and increases their resilience against oxidative species. Via paracrine mechanisms, distant cells benefit from cell-cell communication. The finding that non-thermal plasma triggers hormesis-like processes in keratinocytes facilitates the understanding of plasma-tissue interaction and its clinical application.