Pradeep Lamichhane

University of Warwick · School of Engineering

Plasma jets simultaneously create a wide range of reactive oxygen species (ROS) and reactive nitrogen species (RNS), making selective production challenging. In this study, an attempt was made to address this problem by adjusting the downstream length of the plasma jet to regulate reactive species production in an AC-driven argon plasma jet. Jets w...

This research explores the potential of electric field enforcement in dielectric barrier discharge using specially designed pyramid‐shaped μ‐electrodes for a plasma‐assisted nitrogen fixation process. The obtained results are compared under varying conditions, including the presence and absence of titanium dioxide ( TiO2 ${TiO_2 }$ ), different oxy...

Ammonia (NH3) production is of global concern for today's food supply security and as future energy vector. Plasma technology can add to supply‐chain resilience of fertilizer production and improve the environmental profile using renewable energy; allowing distributed NH3 production. With the objective to provide process intensification of small‐ca...

Over the years, numerous studies have explored the green synthesis of ethylene. Within this context, the focus of this perspective shifts toward plasma technology, which has demonstrated the capability to convert methane into ethylene. Plasma catalysis creates distinctive physical and chemical environments, particularly at normal temperature and pr...

Pesticides have been an integral part of modern agriculture as their use ensures good harvests. However, excessive use of pesticides in the last few decades has caused significant environmental degradation. Moreover, excessive use of pesticides causes stress on crops and non-target plants and exhibits toxicity to other organisms including mammals,...

Plasma-assisted nitrogen fixation has emerged as a promising alternative to conventional nitrogen fixation methods. In this study, we investigate the feasibility of plasma-assisted nitrogen fixation using an AC-driven dielectric barrier discharge generated from the micro-tips of a specially designed fast-modulated pyramid-shaped electrode. The obta...

The conversion of methane into transportable and storable materials is crucial in the petrochemical sector. In this study, a specially constructed AC‐driven dielectric barrier discharge (DBD) that has charge injector pyramids on one of the electrodes and runs at ambient temperature and pressure was used to evaluate noncatalytic methane conversion....

Seed germination is a complex physiological process initiated by water uptake and results in the emergence of radicles and plumules. Because water uptake is a prerequisite for germination, the presence of a hydrophobic or water-impermeable seed coat can limit the process of germination. Therefore, researchers are eager to modify the seed coat surfa...

Plasma jets simultaneously create a wide range of reactive oxygen species (ROS) and reactive nitrogen species (RNS), making selective production challenging. In this study, an attempt was made to address this problem by adjusting the downstream length of the plasma jet to regulate reactive species production in an AC-driven argon plasma jet. Jets w...

This study investigates how addition of a 2nd ground electrode in an argon plasma jet influences the production of hydrogen peroxide (H2O2) in deionised water (DIW). Briefly, plasma is ignited by purging argon gas through a quartz tube at 1 l min−1 and applying a sinusoidal voltage of 7 kV (peak–peak) at 23.5 kHz to a high voltage stainless steel n...

This paper compared the effects of A. indica plant proteins over chemical methods in the morphology of zinc oxide nanoparticles (ZnO NPs) prepared by a co-precipitation method, and ethanol sensing performance of prepared thin films deposited over a fluorene-doped tin oxide (FTO) bind glass substrate using spray pyrolysis technique. The average crys...

This research investigated the capture of nitrate by magnesium ions in plasma-activated water (PAW) and its antifungal effect on the cell viability of the newly emerged mushroom pathogen Cryptococcus pseudolongus. Optical emission spectra of the plasma jet exhibited several emission bands attributable to plasma-generated reactive oxygen and nitroge...

In this study, we used an Ar plasma jet to enhance reactive oxygen and nitrogen species (RONS). Atmospheric air was mixed directly with the working gas through the hole of the quartz tube in the discharge region. The electrical, optical, and chemical characteristics of air-mixed Ar plasma via a hole and pure Ar plasma without a hole were compared a...

Polyethylene glycol-functionalized gold nanoparticles (Au@PEG NPs) were prepared by a simple plasma-assisted method without additional reducing chemicals. After irradiating tetrachloroauric acid (HAuCl4) and polyethylene glycol (PEG) in aqueous medium with an argon plasma jet, the gold precursor transformed into an Au@PEG NP colloid that exhibited...

Nitrogen fixation is crucial for plants as it is utilized for the biosynthesis of almost all biomolecules. Most of our atmosphere consists of nitrogen, but plants cannot straightforwardly assimilate this from the air, and natural nitrogen fixation is inadequate to meet the extreme necessities of global nutrition. In this study, nitrogen fixation in...

Microwave (MW) radiation is increasingly being used for several biological applications. Many investigations have focused on understanding the potential influences of pulsed MW irradiation on biological solutions. The current study aimed to investigate the effects of 3.5 GHz pulsed MW radiation-irradiated liquid solutions on the survival of human c...

Various reactive oxygen and nitrogen species are accompanied by electrons, ultra-violet (UV) radiation, ions, photons, and electric fields in non-thermal atmospheric pressure plasma. Plasma technology is already used in diverse fields, such as biomedicine, dentistry, agriculture, ozone generation, chemical synthesis, surface treatment, and coating....

We explore how to configure an argon atmospheric-pressure plasma jet for enhancing its production of hydrogen peroxide (H2O2) in deionised water (DIW). The plasma jet consists of a quartz tube of 1.5 mm inner diameter and 3 mm outer diameter, with an upstream internal needle electrode (within the tube) and a downstream external cylindrical electrod...

A floating zone plate (ZP) was installed in the axial vircator for the formation of VC2 by using the wall charge of drifting electrons. The material of the opaque zones was changed to aluminum, copper, and glass to observe the effects. The main frequency of the microwave increased when VC2 is formed. At new frequencies, the opaque zones with alumin...

Interactions between atmospheric pressure plasma jet and deionized water surface, Results in Physics (2020), doi: https://doi. Abstract 10 This study describes atmospheric pressure Ar plasma jet interactions with and without 11 deionized (DI) water. The plasma jet was operated under an applied voltage in the range 1.8-12 2.5 kV with a 50 kHz sinuso...

Despite possessing versatile properties and great potential for biomedical research, the number of studies on the application polydopamine-functionalized gold nanoparticles (Au@PDA NPs) remains infrequent due to their preparation procedure, which consists of multiple-steps and employing hazardous redox agents. We herein present an unprecedented sin...

Supplementary information.

In this study, nitrogen fixation in water was achieved using an atmospheric pressure non-thermal nitrogen plasma jet generated by an AC driven source of 10 kV (peak) power supply with a repetition frequency of 33 kHz. Plasmas have been proposed for the excitation of the nitrogen gas, which can be readily converted to ammonia, nitrite, nitrate, and...

In this study, nitrogen �fixation in the electrolyte was achieved by atmospheric pressure non-thermal plasma generated by a sinusoidal power supply (with an applied voltage of 10 kV and a frequency of 33 kHz). Ammonia measurements on plasma exposed electrolyte at several working gas and purging gas conditions revealed that nitrogen plasma on the sa...

In this study, a new mechanism is proposed to develop a second virtual cathode (VC2). An axial vircator was simulated by adding a floating zone plate (ZP) inside the drift tube, which is designed at the dominant frequency of 3.42 GHz. The obtained results indicated that the floating ZP contributes to form a VC2 by using the drifting electrons as wa...

A gas field ion source (GFIS) has several advantages such as high current density, low energy spread, and high brightness. In this study, Helium gas was used in a GFIS, generated using the field ionization and field evaporation processes. The (110) oriented three adatoms tip (TAT) and single atom tip (SAT) were prepared with its ion emission stabil...

Over the past few decades, microwave (MW) radiation has been widely used, and its biological effects have been extensively investigated. However, the effect of MW radiation on human skin biology is not well understood. We study the effects of pulsed high-power microwaves (HPMs) on melanoma (G361 and SK-Mel-31) and normal human dermal fibroblast (NH...

A virtual cathode oscillator (vircator) is a special type of oscillator capable of generating high-power microwaves. We studied an axially extracted vircator by installing a cone-shaped reflector in our pulsed power device, “Chundoong” and numerically studied by using a three-dimensional particle-in-cell simulation, MAGIC. In the simulation, we var...

In this work, a polyvinyl alcohol (PVA) thin film was modified by exposure to a dielectric barrier discharge argon plasma. The plasma was generated by a sinusoidal power supply with discharge voltage of 4.75 kV (rms), and frequency of 30 kHz at duty cycle 6.13%. The effect of the plasma on the PVA thin film was investigated by analyzing the contact...

In this work, a polyvinyl alcohol (PVA) thin film was modified by exposure to a dielectric barrier discharge argon plasma. The plasma was generated by a sinusoidal power supply with discharge voltage of 4.75 kV (rms), and frequency of 30 kHz at duty cycle 6.13%. The effect of the plasma on the PVA thin film was investigated by analyzing the contact...

In this study, ammonia (NH3) vapor was added to atmospheric pressure argon plasma jet generated by sinusoidal power supply (with an applied voltage of 4 kV and frequency of 35 kHz) and it was analyzed by electrical, optical, and chemical probe measurements. A total gas flow rate of 1200 sccm under 2% flow rate of either water or ammonia solution at...

Cold atmospheric pressure plasma jets (plasma) operated in ambient air provide a rich source of reactive oxygen and nitrogen species (RONS), which are known to influence biological processes important in disease. In the plasma treatment of diseased tissue such as subcutaneous cancer tumors, plasma RONS need to first traverse an interface between th...

This work proposes an atmospheric pressure plasma jet operated by the injection of natural air through a hole. The conventional plasma jet was modified by creating a small hole in the quartz tube. A small amount of argon gas flow inside the tube creates a pressure difference with the surrounding environment. By Bernoulli's principle, natural air is...