A5016973721- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Gyrotron and Vacuum Electronics Research
- Crop Yield and Soil Fertility
- Agricultural Science and Fertilization
- Particle Accelerators and Free-Electron Lasers
- Silicon Carbide Semiconductor Technologies
- Electrostatic Discharge in Electronics
- Radioactivity and Radon Measurements
- Plasma Applications and Diagnostics
- Agronomic Practices and Intercropping Systems
- Bangladesh Politics, Society, and Development
- South Asian Studies and Conflicts
- Nuclear and radioactivity studies
- Rice Cultivation and Yield Improvement
- Electron and X-Ray Spectroscopy Techniques
- Electromagnetic Compatibility and Noise Suppression
- Radiation Dose and Imaging
- Soil Management and Crop Yield
- Pulsed Power Technology Applications
- Semiconductor materials and devices
- Sugarcane Cultivation and Processing
- Agriculture, Plant Science, Crop Management
- Lightning and Electromagnetic Phenomena
- Advanced Data Storage Technologies
Michigan State University
2015-2024
University of Faisalabad
2024
University of Agriculture Faisalabad
2024
Oberlin College
2024
Michigan United
2022-2023
Riphah International University
2021-2023
University of Wisconsin–Madison
2022
Wright-Patterson Air Force Base
2019-2020
University of Cambridge
2019-2020
University of Azad Jammu and Kashmir
2004-2020
Abstract Recent progress made in the prediction, characterisation, and mitigation of multipactor discharge is reviewed for single‐ two‐surface geometries. First, an overview basic concepts including secondary electron emission, kinetics under force law, susceptibility, saturation mechanisms provided, followed by a discussion on strategies. These strategies are categorised into two broad areas – engineered devices radio frequency (rf) fields. Each approach useful different applications....
This work investigates multipactor discharge on a single dielectric surface with two carrier frequencies of an rf electric field. We use Monte Carlo simulations and analytical calculations to obtain susceptibility diagrams in terms the field normal due residual charge dielectric. It is found that contrast frequency case, general, presence second increases threshold magnitude initiate multipactor. The effects relative strength phase, separation are examined. conditions minimize mulitpactor derived.
This work presents a multiparticle Monte Carlo simulation model in one dimension with adaptive time steps to investigate the dependent physics of single dielectric surface multipactor. Using this model, we study multipactor discharge on two carrier frequencies. We find that saturation level and oscillation pattern normal field parallel rf frequencies are different from those frequency. Closed Lissajous curves obtained describe temporal relationship between fields ac state.
It is of importance to suppress single-surface multipactor discharges in high power microwave devices. In this work, both particle-in-cell (PIC) and Monte-Carlo simulations demonstrate that can be significantly suppressed by a temporal Gaussian-type transverse electric field waveform. Decreasing the half peak width Gaussian reduce time-averaged positive charge density on surface, corresponding strength multipactor, an order magnitude at fixed input power. The underlying physical mechanism...
This work investigates the time-dependent physics of multipactor discharge on a single dielectric surface with transverse rf electric field two carrier frequencies using multiparticle Monte Carlo simulation model adaptive time steps. The effects relative strength and phase, frequency separation between carriers are studied. Closed Lissajous curves obtained to describe relationship parallel normal charging in ac saturation state. It is found that two-frequency operation can reduce compared...
This work investigates secondary electron yield (SEY) mitigation from a metal surface with microporous array fabricated using the laser drilling technique. We propose general empirical model to fit experimentally measured SEY of flat gold for normal and oblique incidences primary electrons. Using this model, we develop two-dimensional Monte Carlo (MC) simulation scheme determine effective array. It is found that porous significantly reduced compared surface. By taking into account all...
We report exhaustive measurements of the secondary electron yield (SEY) from a gold film containing an array micropores as function angle incidence primary electrons. The SEY are in good agreement with Monte-Carlo (MC) simulations. A highly accurate empirical fit to data incident impact is also proposed. In this study, have aspect ratios (ratio pore height over diameter) ranging about 1.5 3.5. effect density (porosity) and ratio analyzed greater detail. It found that increasing porosity...
This article presents the frequency-domain analysis of multipactor discharge on a single dielectric surface. We employ multiparticle Monte Carlo simulation model in one dimension with adaptive time steps to obtain temporal profiles normal electric field, which is due surface charging that corresponds strength, induced by single- or dual-tone radio frequency (RF) fields acting parallel apply discrete Fourier transform (DFT) amplitude spectrum fields. It found for single-tone RF operation,...
This paper presents two-surface multipactor discharge with two-frequency rf fields using Monte Carlo simulations and Computer Simulation Technology (CST) Particle Studio. The effects of the relative strength phase second carrier mode on susceptibility time dependent physics are studied. Compared to single-frequency operation, shrinkage regions is observed for different configurations operation. presence a in field results mixed modes which electrons take fixed period complete round trip...
We present secondary electron yield (SEY) characterization of high porosity surfaces for multipactor-free microwave components. first calculate the SEYs through using Monte Carlo simulations. demonstrate that these can be treated as homogeneous materials with low effective SEYs. prove a significant SEY reduction is attainable by porosities, and above certain level, entire surface falls below unity, offering multipactor free capability. import resultant into our semi-analytic approach to...
A dimensional method was employed to evaluate the microscale gas breakdown characteristics at atmospheric pressure, resulting in a universal curve applicable different types of gases (e.g., Ar, Xe, Ne, and N2). As gap distance decreases, mode transitions from ion-induced secondary electron emission field regime. In regime, positive space charge effect becomes more significant. We discovered that incorporating regime can be achieved by modifying local electric enhancement factor β....
Unsteady three-dimensional flow of an incompressible Oldroyd-B nanomaterial is reported in this article. The origin time-dependent surface spreading lateral directions transversely taking nanoparticles with zero mass flux. formulated partial differential system reframed by similarity variables into ordinary system. obtained solved the process homotopy analysis for dimensional temperature and concentration nanoparticles. Physical parameter behavior on concentrations examined using graph...
Abstract Citrus (oranges, lemon, mandarin, limes and tangarines) has significant nutritional value in human foods. It is rich source of vitamin C, sugar, organic acids, amino minerals like Ca, Mg various other phytochemicals (flavonoids, hesperidin etc) compounds that are responsible for good health. growing more than one forty countries the world including Pakistan, Brazil, China, Mexico, USA, Spain India.Viral infection inflammation triggers production oxygen free radicals these severely...
Two-surface multipactor with a Gaussian-type waveform of rf electric fields is investigated by employing Monte Carlo simulations and 3D electromagnetic particle-in-cell simulations. The effects the full width at half maximum (FWHM) Gaussian profile on susceptibility time dependent dynamics are studied. threshold peak voltage, as well time-averaged power per unit area for development, increases field compared to that sinusoidal field. voltage increase FWHM decreases. Compared RF operation,...
Restoration, preservation and sustainability of agricultural resources including soil demands biologically economically viable farming practices.For boosting physico-chemical properties from 2012 to 2015, three legumes cowpea, cluster bean soybean were intercropped with sorghum in 40-60, 75-25 100-100 seed blending ratios, while pure stand was kept for comparison.Correlation studies also conducted determine linear or inverse relationship between physiological agronomic attributes green...
Multipactor discharge near an rf window is a key limiting factor in high power microwave systems. In this work, we report special features of dielectric multipactor susceptibility under Gaussian-type waveform as function the density transverse electric field (P¯rf) and normal restoring (Edc) via particle-in-cell (PIC) multiple particle Monte Carlo (MC) simulations. The MC simulations show that, for Gaussian half peak width (Δτ), larger than Δτ/T=0.15 with T = 1 ns repetition period, boundary...
The analysis of uranium in water samples can be very helpful for providing guidelines to the general public regarding necessary remedial measures. A fission-track technique has been applied estimation concentration drinking collected from natural springs Muzaffarabad and hilly areas Reshian, Azad Kashmir. involved simultaneous irradiation with thermal neutrons a sample standard contact track detector, counting fission tracks detector (n, f) nuclear reaction. Uranium concentrations were...