Oxidation Kinetics of Aluminum Powders in a Gas Fluidized Bed Reactor in the Potential Application of Surge Arresting Materials

Abstract

In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part How to cite this paper: Shih, H. (2019) Oxidation Kinetics of Aluminum Powders in a Gas Fluidized Bed Reactor in the Potential Application of Surge Arresting Materials. Materials Sciences and Applications,

A comparative analysis of low intensity ultrasound effects on living cells: from simulation to experiments

“…The polystyrene attenuation coefficient was determined from the formula present in Reference (Takagi et al 2007 ) and by using the values reported by some of us and by other authors (Spigarelli et al 2020 ; Tiong et al 2017 ; Lei et al 2013 ). In the calculation of the air acoustic impedance, the speed of sound in the air and the air density have been taken respectively from the work of Dhiren M Joshi and Shih (Shih and Shih 2019 ; Joshi n.d. ) Parameter Value Description 0.890 [mPa·s] Water dynamic viscosity (Snehota et al 2020 ) 2.485 [mPa·s] Water bulk viscosity (Snehota et al 2020 ) 998 [Kg·m −3 ] Water density (Snehota et al 2020 ) α 0.108 [cm −1 ] Polystyrene attenuation coefficient (Spigarelli et al 2020 ), X Z ps 2.5·10 6 [Pa·s·m −1 ] Polysterene acoustic impedance (Snehota et al 2020 ) Z air 4.017·10 2 [Pa·s·m −1 ] Air acoustic impedance (Racca et al 2020 ; Garino et al 2019 ) r 7.950 [mm] Well basis radius H 10.78 [mm] Solution height L D, 0.30 9.95 [nm] Bottom wall displacement at I input = 0.30 W/cm 2 L D, 0.45 12.19 [nm] …”

“…The polystyrene attenuation coefficient was determined from the formula present in Reference (Takagi et al 2007) and by using the values reported by some of us and by other authors (Spigarelli et al 2020;Tiong et al 2017;Lei et al 2013). In the calculation of the air acoustic impedance, the speed of sound in the air and the air density have been taken respectively from the work of Dhiren M Joshi and Shih (Shih and Shih 2019 Bottom wall displacement at I input = 0.60 W/cm 2 diluted in ethanol with a concentration of 100 μg/mL) on a holey carbon copper grid and dried overnight.…”