Multicomponent-coupled nonlinear Schrodinger-type equations are significant mathematical models that have their origins in numerous disciplines such as the nonlinear optics, theory of deep water waves, plasma physics, and fluid dynamics, and many others. This work is mainly concerned to the study of fractional optical soliton solutions of the truncated fractional three component coupled nonlinear Schrödinger-type system. The study of soliton theory plays a crucial role in the telecommunication industry by the utilization of nonlinear optics. The principal area of research in the field of optical solitons revolves around optical fibers, meta-materials, metasurfaces, magneto-optic waveguides, and other related technologies. Therefore, the observation of these solitons attained significant attention from scholars in recent years. Optical solitons refer to electromagnetic waves that are confined within nonlinear dispersive medium, wherein the balance between dispersion and nonlinearity effects enables the intensity to remain constant. The two recently integration tools, refereed as modified Sardar subequation method and new Kudryashov approach, are under consideration to explore the governing system. In order to solve the system, first a fractional transformation is applied that offers the ordinary differential equation. Then by the assistance of homogeneous balance principle, the suggested methods are applied. We obtain the solutions in different types including mixed, dark, singular, bright–dark, bright, complex and combined solitons. Moreover, the hyperbolic, periodic and exponential function solutions are also extracted. In addition, the effect of fractional parameter has been observed by sketching the different plots. All the obtained solutions in thisTS: Please remove abstract heading study are verified by substitution back into the original equation through the software package Mathematica. The findings demonstrate the efficacy, efficiency and applicability of the computational methods employed. We anticipate that our work will be helpful for a large number of engineering models and other related problems.
Md. Rezwan Ahamed Fahim, Purobi Rani Kundu, M. Islam
et al.
Abstract The (3+1)-dimensional Kadomtsev-Petviashvili and the modified KdV-Zakharov-Kuznetsov equations have a significant impact in modern science for their widespread applications in the theory of long-wave propagation, dynamics of shallow water wave, plasma fluid model, chemical kinematics, chemical engineering, geochemistry, and many other topics. In this article, we have assessed the effects of wave speed and physical parameters on the wave contours and confirmed that waveform changes with the variety of the free factors in it. As a result, wave solutions are extensively analyzed by using the balancing condition on the linear and nonlinear terms of the highest order and extracted different standard wave configurations, containing kink, breather soliton, bell-shaped soliton, and periodic waves. To extract the soliton solutions of the high-dimensional nonlinear evolution equations, a recently developed approach of the sine-Gordon expansion method is used to derive the wave solutions directly. The sine-Gordon expansion approach is a potent and strategic mathematical tool for instituting ample of new traveling wave solutions of nonlinear equations. This study established the efficiency of the described method in solving evolution equations which are nonlinear and with higher dimension (HNEEs). Closed-form solutions are carefully illustrated and discussed through diagrams.
The standard method for applying hydroxyapatite (HAp) coatings to biomedical implants is plasma spraying. However, due to the high temperature of the plasma, these coatings frequently experience negative effects like evaporation, phase change, de-bonding, gas release, and residual stresses. This paper summarizes a revolutionary technique known as a cold spray (CS), which allows HAp coatings to be applied at temperatures well below their melting point. CS has several advantages over conventional high-temperature technologies, and it seems to be approaching parity with other older methods. When applied using the CS approach, the HAp coatings enhance bioactivity, increase corrosion resistance, and maintain the characteristics of calcium phosphate ceramics. This study aims to give a concise and comprehensive overview of HAp-based materials, including substituted-HAp and HAp/polymer composites, and their applications in bone tissue engineering. To better understand the advantages of CS technology, a comparison of CS, high-velocity oxy-fuel (HVOF), and plasma spray is given at the end. The perspective and difficulties were also highlighted.
We review spectroscopic methods developed for the determination of magnetic fields in high-energy-density (HED) plasmas. In such plasmas, the common Zeeman-splitting magnetic-field diagnostics are often impeded by various broadening mechanisms of the atomic transitions. The methods described, encompassing atomic transitions in the visible and ultraviolet spectral regions, are applied to the study of imploding plasmas (in a Z-pinch configuration) with and without pre-embedded magnetic fields, relativistic-electron focusing diodes, and plasma-opening switches. The measurements of the magnetic field in side-on observations of cylindrical-plasma configurations that are local in the radial direction despite the light integration along the chordal lines of sight are discussed. The evolution of the magnetic-field distributions obtained, together with the measurements of the plasma temperature and density, allows for studying the plasma dynamics, resistivity, and pressure and energy balance. In particular, for the Z-pinch, an intriguing question on the current flow in the imploding plasma was raised due to the observation that the current during stagnation mainly flows at relatively large radii, outside the stagnation region. For the premagnetized plasma implosions, all three components of the magnetic field (azimuthal, axial, and radial) were measured, yielding the evolution of the current flow and the efficiency of the axial field compression, as well as the relation between the geometry of the field and the plasma rotation, found to develop in this configuration. The measurements in the relativistic electron diode are used to quantify the shielding of the magnetic field by the plasmas in the diode. Also described are the experimental and theoretical investigations of a nondiffusive fast penetration of magnetic field into a low-density plasma (in the plasma-opening-switch configuration).
Machine learning methods have shown potential for the optimization of production processes. Due to the complex relationships often inherent in those processes, the success of such methods is often uncertain and unreliable. Therefore, understanding the (algorithmic) behavior and results of machine learning methods is crucial to improve the prediction of production processes. Here, mathematical tools may help. This paper shows how efficient algorithms for the training of neural networks and their retraining in the framework of transfer learning are expressed in a discrete as well as a time-continuous formulation. The latter can be analyzed and investigated using mathematical techniques from kinetic gas dynamics. The results obtained provide a first step towards explainable artificial intelligence. Based on the mathematical description, an adapted ensemble method for retraining of neural networks is proposed and compared with backpropagation algorithms. The process of training and retraining is a common task and therefore demonstrated for two very different production processes. The first one involves the prediction of specific cutting forces and the second one the prediction of particle properties in a plasma spraying coating process. For both use cases, the presented algorithms are applied and their performance is evaluated giving thereby an indication how mathematically inspired methods improve classical tasks in production processes.
Negative atomic hydrogen ion (H−) densities were measured in a pulsed low-pressure E-mode inductively-coupled radio-frequency (rf) driven plasma in hydrogen by means of laser photodetachment and a Langmuir probe. This investigation focuses on the influence of different metallic surface materials on the volume production of H− ions. The H− density was measured above a thin disc of either tungsten, stainless steel, copper, aluminium, or molybdenum placed onto the lower grounded electrode of the plasma device as a function of gas pressure and applied rf power. For copper, aluminium, and molybdenum the H− density was found to be quite insensitive to pressure and rf power, with values ranging between 3.6 × 1014 to 5.8 × 1014 m−3. For stainless steel and tungsten, the H− dependency was found to be complex, apart from the case of a similar linear increase from 2.9 × 1014 to 1.1 × 1015 m−3 with rf power at a pressure of 25 Pa. Two-photon absorption laser induced fluorescence was used to measure the atomic hydrogen densities and phase resolved optical emission spectroscopy was used to investigate whether the plasma dynamics were surface dependent. An explanation for the observed differences between the two sets of investigated materials is given in terms of surface reaction mechanisms for the creation of vibrationally excited hydrogen molecules.
Abstract The dome and reflector plate are the parts of divertor plasma facing components (PFCs) of ITER tokamak which are mainly aimed for the removal of heat load of maximum 5 MW/m2 in steady state condition. The dome is a curved tungsten armoured component and the reflector plate is a straight component. These components have multi-layered joints made of various materials such as tungsten (W), OFHC copper (Cu), copper alloy (CuCrZr) and stainless steel (SS316LN). Joining of such multi-layered joints is known to be problematic due to joining of several dissimilar materials. In this paper, we report the indigenous development of medium size dome and reflector plate via vacuum brazing route for ITER like tokamak application. In order to evaluate the performance of the dome against ITER-like scenarios (maximum heat flux removal of 5MW/m2), the dome has been successfully tested for 1000 number of steady-state thermal cycles at incident heat fluxes of 3.87 MW/m2 in the High Heat Flux Test Facility (HHFTF) at IPR. Subsequent testing of additional 200 thermal cycles was also done at incident heat flux of 6 MW/m2. During the High heat flux (HHF) tests, surface temperature of W tiles reached 640oC and the beam power was restricted at 6MW/m2 to limit the temperature below 450oC at the CuCrZr heat sink. Total 1200 steady-state thermal cycles have been completed. At 6 MW/m2, the absorbed heat flux was 4 MW/m2. Engineering analysis on the HHFT of the dome has been performed using Finite element method (FEM) and Computational Fluid Dynamics (CFD) to simulate and to correlate with the experimental data. Ultrasonic immersion technique – Non destructive testing (NDT) was used to inspect the brazed joint quality of the dome before and after the HHFT. The results of the experimental details, engineering analysis and methodology adopted to fabricate the medium size dome and reflector plate are presented here.
Field emission based microplasma actuators generate highly non-neutral surface discharges that can be used to heat, pump, and mix the flow through microchannels and offer an innovative solution to the problems associated with microcombustion. They provide a constant source of heat to counter the large heat loss through the combustor surface, they aid in flow transport at low Reynolds numbers without the use of moving parts, and they provide a constant supply of radicals to promote chain branching reactions. In this work, we present two actuator concepts for the generation of field emission microplasma, one with offset electrodes and the other with planar electrodes. They operate at input voltages in the 275–325 V range at a frequency of 1 GHz which is found to be the most suitable value for flow enhancement. The momentum and energy imparted by the charged particles to the neutrals as modeled by 2D particle-in-cell with Monte Carlo collisions are applied to actuate flow in microchannels using 2D computational fluid dynamics modeling. The planar electrode configuration is found to be more suitable for the purpose of heating, igniting and mixing the flow, as well as improving its residence time through a 10 mm long microcombustor. The combustion of hydrogen and air with the help of 4 such actuators, each with a power consumption of 47.5 mW cm−1, generates power with an efficiency of 90.5%. Such microcombustors can be applied to all battery based systems requiring micropower generation with the the ultimate goal of ‘generating power on a chip’.
In this work, we, for the first time, present the experimental study of complex plasmas in glow discharge in the narrow region of the current channel under magnetic fields up to 104 G. We obtain the conditions for the existence and stability of structures under the whole range of the magnetic field. We could detect a record‐breaking rotation velocity of the dusty structure, reaching 15 rad/s. Measurements of the angular velocity behaviour under varied magnetic fields were performed. In order to characterize the geometry of the dusty structure as a function of the magnetic induction, the size and shape of the sections normal to the discharge axis were measured. The inter‐particle distance as another informative characteristic was fixed for structures under a whole range of the applied magnetic field. Based on the results of the mentioned observations, we propose a qualitative interpretation of the rotation variation with the magnetic field. This interpretation includes the model of mechanisms driving the rotation of the dusty structure.
Generation of the defect particles during the plasma-assisted metal dry etching process is induced by the various mechanisms. Most of these mechanisms are caused by the non-volatility of metal-halide compounds generated during the etching process. Degeneration of the metal etching process chamber condition is observed as the frequent process fault caused by the defects, but the worse condition is not recovered by itself. Because of this property of the metal etching process, proper work of the preventive maintenance (PM) to restore the process chamber or the addition of a discharge cleaning step is required periodically. However, inadequate PM or discharge cleaning by the uncertain cause analysis of the defect generation should be a just temporary remedy, and might lead the repetition of similar problems. To solve this problem, the virtual metrology (VM) model based on the plasma information (PI) parameters, known as PI-VM, was developed and applied for the defect control of the metal layer dry etching processes in organic light emitting diode (OLED) display manufacturing. To obtain the information about the generation rates of non-volatile compounds and their removal rates by the exhaustion system, PI parameters are designed with the consideration of the reaction kinetics in the metal etching plasma volume, sheath, and reacting surface using the big data of equipment engineering system (EES) and optical emission spectroscopy (OES) accumulated during the mass production process. The developed PI-VM index could be applied to a 2–3 h earlier alarm system for the defect occurrence, and had succeeded over 90% of alarm rate. This PI-VM alarm was applied to predictive control of the process by the early substitution of the discharge cleaning step or by the repair of the proper parts in the process chamber. By the control of processes based on the predicted results of the PI-VM, management of the mass production line with about 30% decreased defect was possible in OLED display manufacturing.
In the present research, plasma jets form from Joule heating and ablation of a radial foil (approximately 15 μm thin disk) using a pulsed power generator (COBRA) with 1 MA peak current and 100 ns rise time. We study the effects on jet dynamics resulting from varying an applied uniform axial magnetic field (Bz) from 0 to 2 T. We empirically observe a disruption of the plasma jet collimation, for which plasma is ej ected from the foil as discrete bursts and does not form an azimuthally symmetric plasma jet. The critical Bz for the disruption depends upon the foil material (Al, Ti, Ni, Cu, Zn, Mo, W). The disruption initiates from the foil surface and is dependent upon material properties such as electrical conductivity and equation of state. The applied Bz acts with the higher conductivity materials to facilitate nonuniform plasma and current filamentation that breaks the azimuthal symmetry needed to form the plasma jet. The plasma filamentation likely originates from initial perturbations (in density and resistivity) in the higher-density solid-liquid phases. 3D numerical simulations in Cartesian coordinates (using the extended magnetohydrodynamics code, PERSEUS) of a section of the ablating foil reproduce some of the experimental trends including the external magnetic field dependence and material resistivity dependence of the generation of plasma and current nonuniformities.
We compare MHD simulation results to experimental measurements taken from a dense plasma focus driven by the HAWK pulsed-power generator (0.65 MA peak current, $1.2\mu \mathrm{s}$ rise time). USim is a 3D capable, fluid plasma modeling framework that simulates the dynamics of charged fluids using the two temperature MHD equations, among others. The DPF device is modeled using an unstructured mesh, and initial conditions are applied to account for plasma injected radially inward by 3 Marshall guns, as well as additional mass injected by an on-axis gas puff valve. The non-axisymmetric nature of the Marshall guns means that full 3D simulations are required. The initial plasma and gas density profiles were varied to determine their effect on the pinch parameters. Simulated current, voltage, inductance and neutron yield are compared with experimental results. We also calculate simulated end-on optical imaging using multiple opacity models and compare with experiment.
Increasing the life time of semiconductors during the excitation process is an important challenge and the results presented in the article can be used in determining the threshold of pumping process using an electron beam to avoid growing nonlinear waves which can deliver the energy through the material to produce defects1,2. The method now depends on engineering treatment which expensive, and so it is necessary to find another solution to the problem. The quantum fluid model which characterized by degenerate pressures, exchange correlation effect, and Bohm potential is constructed for a system of (electron/hole) and electron beam. Also, the soliton solution for the Kadomtsev-Petviashvili equation (KP) which derived from the reductive perturbation theory is obtained. The model had been applied to GaAs semiconductor and the numerical results showed that both the streaming and temperature of the electron beam have a significant effect on growing the solitary waves.