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Microscale Plasmas for Metal and Metal Oxide Nanoparticle Synthesis
Published in R. Mohan Sankaran, Plasma Processing of Nanomaterials, 2017
Davide Mariotti, R. Mohan Sankaran
Confining plasmas to small dimensions results in new physical behavior. Two general parameters that vary as the size of a plasma is decreased are the surface-to-volume ratio and the electrode spacing. The surface-to-volume ratio, which increases as the size of the plasma decreases, alters the overall energy balance and leads to plasma stability (or instability) within different regions of the operating parameter space. Decreasing the electrode spacing changes the electric field distribution and, thus, impacts the charge distribution and overall plasma neutrality. Overall, these effects have strong implications on the energy distribution of the different species (electrons, ions, radicals, neutrals) and on the physical structure of the plasma, either simultaneously or independently. There is now significant evidence in the literature that these transitions take place when the dimensions of the plasma are reduced to the micron scale.8–11 Traditional properties and scaling laws for plasmas do not hold at these dimensions, justifying the existence of a different regime of operation, hereafter referred to as the microplasma regime (MPR).
Modelling sodium requirements of athletes across a variety of exercise scenarios – Identifying when to test and target, or season to taste
Published in European Journal of Sport Science, 2023
This study aimed to use the equation of Kurtz and Nguyen (2003), previously validated during exercise to predict post-exercise [Na+]plasma, to predict sodium replacement requirements during exercise for [Na+]plasma stability. Through modelling, the effect of different variables on the calculated requirements could be observed. It was shown that when sodium intake is expressed as a proportion of losses, a clear pattern is established whereby in most circumstances no sodium intake is necessary unless ≥70% of sweat fluid losses are replaced, and minimal or no sodium intake is required when [Na+]sweat is ≤40 mmol·L−1, except when ≥90% of sweat fluid losses are replaced. These findings are robust to changes in sweat rate, exercise duration, and baseline body mass, and are only subtly influenced by [K+]sweat or baseline [Na+]plasma. When examining real-world sporting scenarios, sodium intake is not required during a soccer match or elite marathon race unless sweat rate is high, [Na+]sweat is high, and fluid is aggressively replaced. However, sodium was required for maintenance of [Na+]plasma during a 160 km ultramarathon when [Na+]sweat was above average (≥ 40 mmol·L−1), and fluid replacement targeted a ≤2% TBW loss in such scenarios (i.e. fluid intake >1.2 L·h−1).
Instability of magnetosonic waves in magnetized degenerate half-spin-polarized quantum plasma
Published in Waves in Random and Complex Media, 2023
W. F. El-Taibany, P. K. Karmakar, A. A. Beshara, M. A. El-Borie, S. A. Gwaily, A. Atteya
The growth rate of modified dust acoustic solitary waves (DASWs) and the instability criterion are discussed [25]. The four-component dusty plasma stability has been investigated [26]. The magnetized dusty plasma was studied using the extended Zakharov–Kuznetsov equation [27,28]. The Hirota method [27] was used to obtain bilinear forms and soliton solutions. They discovered that the nonlinear coefficient A has a positive effect on the soliton amplitude, whereas the dispersion coefficients B and C have a negative effect [27]. Furthermore, it was discovered that the polarization parameter affects the instability growth rate for both positively and negatively charged dust [29] when studying solitary waves with the polarization force effect. El-Taibany et al. investigated the DASWs' instability in the presence of an external static magnetic field [29]. They discovered that superthermal electron and ion densities influence the rate of instability growth. El-Taibany et al [30] investigated the three-dimensional modulational instability of dust acoustic waves in the presence of generalized (r,q) distributed electrons. They discovered that the spectral parameters of the generalized (r, q) distribution and the electron-to-ion temperature ratio have a strong influence on the domain of the stability and instability regions.
Estimation and Uncertainties of Profiles and Equilibria for Fusion Modeling Codes
Published in Fusion Science and Technology, 2020
R. Fischer, L. Giannone, J. Illerhaus, P. J. McCarthy, R. M. McDermott
For the analysis and prediction of plasma performance, plasma stability, and power and particle exhaust, sophisticated transport and stability codes, e.g., GENE (Ref. 1) and SOLPS-ITER (Ref. 2), are routinely used. The results of modeling codes do critically depend on reliable profile and equilibrium estimates. Frequently, the results of these codes are interpreted without quantifying their reliability. The propagation of uncertainties (UP) of input quantities to the results of modeling codes is frequently not considered. The situation becomes even more cumbersome if profile gradients and their uncertainties are of major concern as in transport and stability analyses. The present work addresses the uncertainty quantification of input quantities applying different methods of estimating profiles and equilibria and their uncertainties for use in modeling codes.