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This paper presents a recently developed full kinetic particle simulation code package, which is a two-dimensional highly integrated and universal framework for low-temperature plasma simulation on both Cartesian and axisymmetric coordinate systems. This code package is named CFIRM, since it is designed based on the continuous Galerkin immersed-finite-element (IFE) particle-in-cell (PIC) model with the polynomial-preserving-recovery (PPR) technique and the Monte-Carlo-collision (MCC) method. Both the traditional and implicit PIC methods were implemented in the package. Incorporating the advantages of all these methods together, the CFIRM code can adopt explicit or implicit PIC schemes to track the motion trajectory of charged particles and deal with the collisions between plasma and neutral gas. Additionally, it can conveniently handle complex interface problems on structured grids. The CFRIM code has excellent versatility in low-temperature plasma simulation and can easily extend to various particle processing modules, such as the variable weights and adaptive particle management algorithms which were incorporated into this code to reduce the memory utilization rate. The implementation for the main algorithms and the overall simulation framework of the CFIRM code package are rigorously described in details. Several simulations of the benchmark cases are carried out to validate the reliability and accuracy of the CFIRM code. Moreover, two typical low-temperature plasma engineering problems are simulated, including a hall thruster and a capacitively coupled plasma reactor, which demonstrates the applicability of this code package. [ABSTRACT FROM AUTHOR]

Plasma gas phase synthesis of graphene method is one-step synthesis, without catalyst, acid, solvent and substrate materials. In this paper, plasma pyrolysis of C2H4 for the preparation of graphene was carried out to investigate the effect of doping H2, CO2, and N2 on the morphology characteristics and chemical reaction properties of the synthesized products at different reaction temperatures ranging from 1500 to 4500 K. It was found that an increase in temperature leads to flatter morphology, less agglomeration, and a decrease in defect density and oxygen content in graphene. The addition of H2, CO2, and N2 gases affected the morphology and defect density of the products. In addition, the high temperature conditions increase the hydrogen atom concentration and etch the edges of graphene, while CO2 slows down the etching process and decreases the defect density. Doping with high enthalpy N2 favors the improvement of crystallinity and defect density at low temperatures, but increases the defect density at high temperatures. These findings contribute to further understanding of the application and optimization of the method of plasma gas phase synthesis of graphene. [ABSTRACT FROM AUTHOR]

Laser-induced plasma ignition is a new ignition method to achieve stable and reliable ignition of liquid rocket engines. It has the advantages of accurate and controllable ignition position, broadening ignition lean-burn limit and small disturbance to flow field. In this paper, the laser ignition process and combustion characteristics of gas oxygen/gas methane under rocket engine conditions are studied from four aspects, namely different ignition positions, ignition energy, fuel-oxygen momentum ratio and chamber pressure. Using a high-speed camera, the dynamic process of ignition was captured by the shadow method, and the generation and propagation of laser-induced flame nuclei were recorded. The results show that at the airflow velocity of 300–400 m/s, the time required for the flame kernel to develop to the entire combustion chamber is about 300 μs, and the time for the flame to reach a steady state is tens of milliseconds. When the ignition energy is increased by 1.5 times, the time required for the flame kernel to develop from the recirculation zone to the mainstream zone is shortened to 1/3 of the original; with the increase of the fuel-oxygen momentum ratio, the shape of the initial flame kernel changes from round to oval, and the development speed of the flame kernel also increases. The fuel-oxygen momentum ratio increases from 0.59 to 2.75, and the time required for the flame kernel to develop from the recirculation zone to the mainstream zone decreases from 167 μs to 56 μs＀ Except chamber pressure, other factors have no effect on the pressure rise rate of the ignition process, and the higher the chamber pressure, the faster the pressure rise rate; in order to avoid deflagration, the shear layer is more suitable as the ignition position. With the increase of ignition energy, fuel-oxygen momentum ratio and chamber pressure, the development speed of flame kernel increases, but the shape and development process of flame kernel will be different under the influence of different factors. • Laser ignition is carried out in a highly complex engine environment with high pressure and non-premixed flow field. • The higher the chamber pressure is, the faster the pressure rises during ignition. In order to avoid deflagration, the shear layer is more suitable for ignition. • The trend of flame kernel development rate increases with the increase of ignition energy, fuel-oxygen momentum ratio and chamber pressure. [ABSTRACT FROM AUTHOR]

Tsallis nonextensive statistical mechanics (or q-statistics) has been used for the first time to study pulsating auroras, which are regularly observed in the auroral ionosphere during geomagnetic disturbances. For systems in which long-range interactions, such as ionized gas or plasma, take place and whose dynamics are determined primarily by long-range electromagnetic forces, it can be expected that nonadditive and nonextensive thermostatistic principles can characterize their macroscopic behavior. In this paper, we argued that pulsating auroras exhibit nonextensive properties and can be described, among other things, by q-statistics. We have also demonstrated that the non-extensive parameter q correlates well with the flatness index and with the scaling index, which indicates the applicability of this approach for auroral glow. Thus, q-statistics can be used to analyze phenomena in the high-latitude region of the Earth. [ABSTRACT FROM AUTHOR]

Non‐thermal plasma (NTP) catalysis, mirroring the trend towards non‐conventional electron‐mediated molecular activation, unfolds novel routes for chemical reactions. Operating at ambient pressure, lower temperatures, and energized by electricity that can powered by renewable sources, NTP offers a cost‐effective and efficient means of sustainable fuel production. This approach has the potential to revolutionize the oil and gas industry, meeting current energy demands while circumventing the challenges posed by conventional thermal catalysis processes, thereby enhancing environmental sustainability and energy security. Through an exploration of the synergistic effects between plasma, catalysis, and hydrocarbon molecules, this concept paper emphasizes the significant advancements made in in‐liquid plasma catalysis strategies for fuel production from heavy oil upgrading. We also provide insights into the heterogeneous catalyst design and the role of plasma gas as an additional catalyst for achieving efficient and sustainable energy solutions. The prospects of in‐liquid plasma catalysis, emphasizing its transformative role in shaping the energy future, are also discussed. [ABSTRACT FROM AUTHOR]

This paper comprehensively investigates the oblique propagation of ion-acoustic solitary waves (IASWs) with arbitrary amplitude in a magnetoplasma consisting of inertialess non-Maxwellian (nonthermal) electrons, inertialess Maxwellian positrons, and inertial adiabatically heated ions. It is postulated that the positive ions demonstrate adiabatic behavior that is distinguished by anisotropic thermal pressure. The study utilizes Sagdeev's pseudopotential theory to analyze the fluid equations of the plasma model and reduce them to the energy equation. Different plasma configuration factors, such as nonthermal parameters, positron concentration, and parallel and perpendicular ion pressure, are being studied to see how they affect the properties of solitary waves with large amplitudes. The findings demonstrate the simultaneous coexistence of compressive and rarefactive IASWs, significantly influenced by positrons and nonthermal electron parameters. The study provides valuable insights into wave phenomena in magnetized plasmas and presents possible applications in both Space and laboratory plasma environments. [ABSTRACT FROM AUTHOR]

Resonance and interference phenomena in waveguide systems are remarkable for control of electromagnetic wave propagations, with extensive applications in many areas. This paper introduces a plasma-dielectric-plasma (PDP) waveguide supporting multiple Fano resonances, made of a tooth cavity directly connected to a straight waveguide and a rectangle cavity with plasma holes. Different from metal-insulator-metal (MIM) waveguides at the near-infrared band with nanoscales, the PDP works in the microwave regime and with centimetre dimension. Furthermore, it has a prominent advantage in tunability due to inherent properties of gaseous discharge plasmas. A finite element method is adopted to study transmission responses and field distributions in details. Also, coupled mode and standing wave theories are applied to confirm the validity of numerical results and theoretically analyze Fano spectra, respectively. Results indicate that the number and position of Fano resonances can be modulated by adjusting the number of plasma holes and altering the plasma frequency, respectively. Also, the independent tunability of multiple Fano resonances can be verified by the additional structure. The numerical simulations provide a reference for plasma to modulate electromagnetic waves and may open up a new path for developing tunable microwave devices, especially in the parallel processing of microwave signals. [ABSTRACT FROM AUTHOR]

In this paper, the elemental composition and morphology of fly ash particles after wood pellets combustion in low-power domestic boiler and removed by electrostatic precipitator were investigated by EDS, XRD and SEM methods. The gaseous products discharged into the atmosphere were identified by the FTIR method. Because fly ash particles are usually exhausted to the atmosphere, new constructions of small electrostatics precipitators for domestic use were proposed in recent years in the literature, for the collection of fly ash particles emitted by such boilers fired by biomass fuel (wood pellets) or by coal. The goal of this study was to characterize the combustion products retained at various places from boiler to stack, i.e., beneath the grating (as bottom ash), on heat exchanger, inner walls of stack, and the collection electrodes of electrostatic precipitator. It was shown that the precipitated biomass fly ash comprises of large irregular particles, which were the agglomerates of primary nanoparticles or unburned fragments of fuel (biomass pieces). These particles were composed mainly of K, Cl, Ca, C, O, P and S (>1 at.%). • Properties of biomass fly ash produced by low-power boiler were investigated. • The speciation of various elements of biomass fly ash particles was presented. • The obtained elemental composition from biomass was compared with coal fly ash. [ABSTRACT FROM AUTHOR]