arXiv subjects

Ramin Mehrabifard

Publications and source records attributed to Ramin Mehrabifard.

8 recordsLinked to original sources

arXiv2026

Plasma-activated water and phenolic compounds: A potent combined strategy against yeast resilience

Effective fungal control is essential to prevent spoilage, contamination, and infections in food, healthcare, and industrial environments. This study explores the antifungal activity of plasma-activated water (PAW), generated by transient spark (TS) electrical discharge, combined with natural phenolic bioactive compounds against the planktonic growth, biofilm formation, and surface adhesion of the yeasts Saccharomyces cerevisiae and Wickerhamomyces anomalus. The phenolic compounds were tested at concentrations of 1 or 2 mg/mL for planktonic growth after determining their minimum inhibitory concentrations. Biofilms were grown on sterile microscope slides for 48 h, stained with acridine orange or calcofluor, and examined using fluorescence microscopy. PAW was used immediately after the plasma treatment of tap water to prepare PAW-phenolic solutions. The combinations of PAW with cinnamic acid and vanillin demonstrated the strongest antiyeast activity against planktonic growth, biofilm formation, and surface adhesion. Biofilms exposed to the PAW-phenolic combinations were notably fragmented, and the residual cells exhibited structural damage. Complete inhibition of biofilm formation was observed when 500 microg/mL cinnamic acid was combined with PAW. These findings demonstrate the potential of combining PAW with selected phenolic compounds as an effective and sustainable strategy for controlling fungal growth.

physics.bio-ph↗

arXiv2026

Two-dimensional simulation of Argon dielectric barrier discharge (DBD) in plasma actuator structure with COMSOL Multiphysics

Dielectric barrier discharge (DBD) plasma is used for various applications. DBD is also one of the most efficient and low-cost methods for active fluid flow control. In this study, a detailed physical model of DBD in atmospheric pressure at 1kV DC voltage is developed with COMSOL Multiphysics software. Argon gas is also used as a background gas and electrodes are assumed to be copper. Plasma parameters such as electron and ion density, electric field, potential, and temperature for different distances of electrodes (1.0mm, 0.9mm, 0.8mm) have been investigated. Moreover, the effect of dielectric type (Quartz, Silica Glass, Mica) on these key parameters is investigated. The results of the simulation show that the longitudinal distance of the buried electrodes to the exposed electrodes has a direct influence on parameters such as electron temperature, and electron and ion density which are the main factors of fluid flow control. These parameters have the maximum value when mica is used as a dielectric and the lowest value when silica glass is utilized.

physics.plasm-ph↗

arXiv2026

Electrohydrodynamic wind generation in planar DBDs: role of electrode symmetry and geometry

This study experimentally and numerically investigates the electrohydrodynamic (EHD) interaction produced by a surface dielectric barrier discharge (SDBD) plasma actuator at atmospheric pressure. The non-thermal dielectric barrier discharge generates ionic wind, which is characterized using a symmetric annular actuator composed of concentric ring and disk electrodes. Unlike conventional linear SDBD actuators that primarily produce tangential airflow, this annular configuration generates a predominantly vertical ionic-wind jet. The effects of electrode diameter D and thickness delta on the induced wind velocity perpendicular to the electrode plane are systematically examined. The experimental results show a maximum wind velocity of 3.42 m s^{-1} for an optimized electrode configuration with D = 32 mm and delta = 0.06 mm. Numerical plasma-fluid simulations support the experimental trends and provide spatial distributions of airflow velocity, electrohydrodynamic volumetric force, electron temperature, and gas pressure in the plasma region. Additional diagnostics based on ozone concentration measurements and Schlieren imaging show that electrodes with larger diameters, particularly 22 and 32 mm, enhance the height and development of the vertical flow, while increasing electrode diameter also promotes ozone production. The results demonstrate an important trade-off between ionic-wind performance and reactive byproduct generation. These findings provide practical guidance for optimizing annular dielectric barrier discharge plasma actuators for active flow control, air purification, ozone-assisted disinfection, and biomedical plasma applications.

physics.plasm-ph↗

arXiv2025

Growth of Phaseolus vulgaris in Response to Seed Priming by Plasma-Activated Water in Laboratory Screening and Outdoor Pot Trial

This study explores plasma-activated water (PAW) effects on Common bean growth in laboratory and pot trials. Three treatments were assessed: PAW priming, spraying, and their combination. Laboratory trials showed no germination improvement. However, pot trials revealed notable increases in seedling length, biomass, and antioxidant enzyme activity. Enzymes SOD, G-POX, CAT, APX, and GR showed significantly higher activity in PAW-treated plants. These effects were linked to reactive oxygen and nitrogen species in PAW. Findings suggest PAW enhances bean growth and physiology, supporting field farming applications.

physics.plasm-ph↗

arXiv2025

Comparison of the Impacts of Three Types of Plasma-Activated Water on the Seed Germination and Plant Growth of Lettuce (Lactuca sativa)

Cold air plasma typically generates reactive oxygen and nitrogen species (RONS), which are transported into water to produce plasma-activated water (PAW). This study examines the effect of PAW produced by three different plasma systems on lettuce: transient spark, fountain dielectric barrier discharge, and microwave plasma. Physiochemical PAW properties and concentrations of RONS (ozone, hydrogen peroxide, nitrite, and nitrate) were measured. Seed germination parameters were recorded in 8-day paper tests. The effect of PAW irrigation was investigated after 6 weeks of plant growth in the soil by measuring the germination rate, plant and root length, dry and fresh plant weight, number of leaves, and photosynthetic pigments. PAW, dependent upon its RONS contents, enhances plant development and affects its physiological parameters.

physics.plasm-ph↗

arXiv2025

Numerical investigation of the effect of high voltage frequency on the density of RONS species in the air atmospheric pressure gas discharge

In the last few decades, studies in various fields of plasma technology have expanded and its application in different processes has increased. Therefore, the achievement of a desirable and practical plasma with specific characteristics is of particular importance. The frequency of the applied voltage is one of the important factors that play a role in the physical and chemical characteristics. In this research, changes in the density of active species produced in an electrical discharge using a dielectric barrier and air working gas have been investigated from a frequency of 500 Hz to 500 kHz, and by applying a constant voltage of 2 kV, have been investigated. For this purpose, 87 different reactions with specific collision cross-sections were defined in COMSOL Multiphysics. Other parameters, including current-voltage waveform, electric field, and species densitywere evaluated. The results show that under completely identical conditions, the electron temperature distribution changes with increasing applied frequency, and the density of reactive oxygen and nitrogen species RONS decreases, but O shows an increasing trend. It should be noted that the simulation results are in good agreement with previous experimental and simulation reports. These results offer valuable insights into optimizing plasma parameters for different applications, potentially resulting in better treatment outcomes across a range of therapeutic domains.

physics.plasm-ph↗

arXiv2024

A numerical analysis of the impact of gas pressure and dielectric material on the generation of body force in an air gas plasma actuator

Plasma technology has undeniably revolutionized industrial processes in recent decades. Atmospheric pressure plasma (APP) has emerged as a prominent and widely applicable tool in various scientific disciplines. Notably, plasma-assisted flow control has become a subject of intense interest, particularly applying surface dielectric barrier discharge (SDBD) plasma actuators for aerodynamic flow control. In this study, a two-dimensional model of the SDBD plasma actuator is developed using the COMSOL Multiphysics program, incorporating air gas discharge reactions with N2/O2/Ar gases in specific ratios (0.78, 0.21, 0.01). The investigation focuses on the impact of dielectric materials (mica, silica glass, quartz, and polytetrafluoroethylene (PTFE)) on plasma characteristics and body force within the plasma actuator under constant input parameters. Moreover, the study explores how variable pressure (760, 660, and 560 torr) in different applications influences plasma properties, ultimately affecting the magnitude of the body force in the plasma actuator. These findings contribute to optimizing plasma technology for flow control applications and enhance industrial efficiency and performance.

physics.plasm-ph↗

arXiv2023

Physical understanding of the static magnetic field's synergistic enhancement of cold atmospheric pressure plasma treatment

In the last decades, to improve the CAP treatment efficiency, its biological effects in combination with other physical modalities have widely investigated. However, the physical insight into most of supposed synergistic effects remained elusive. In this regard, the synergetic effect of cold plasma and magnetic field has been used for different applications, especially due to considerable synergistic in biological media reactivity. In the present paper, using a 420 mT N42 magnet, the effect of the perpendicular external static magnetic field (SMF) on the cold atmospheric pressure plasma (CAP) characteristics, such as electron temperature and density, are investigated based on the optical emission spectroscopy, utilizing the Boltzmann plot method, Saha-Boltzmann equation and Specair software simulation. Results showed that the rotational and electronic excitational temperature experienced 100 K and 550 K increases in the presence of SMF, respectively. While the vibrational and translational temperatures remained constant. Moreover, electron temperature estimated as 1.04 eV in the absence of SMF and increased up to 1.24 eV in the presence of SMF. In addition, the Saha-Boltzmann equation illustrated that the electron density increased in presence of the additional SMF. The results of the present study indicated that the magnetic field could be an assistant to the cold plasma effect, beneficial in medical applications due to modifications in plasma temperature and electron density.

physics.plasm-ph↗