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A Lattice-Boltzmann model coupled with boundary method is proposed for the hydrodynamic resolved simulation of a single char particle combustion. A pure lattice Boltzmann scheme with multi distribution functions is presented for this low Mach reactive flows. Real varying thermodynamic and transport properties are considered, and the fluid density can bear significant change depending on the varying temperature and species concentrations. The recently proposed boundary-thickening based direct forcing-immersed boundary method is extended to implement the boundary conditions of velocity, temperature, and species concentrations at the char particle surface. Two heterogeneous reactions at particle surface and one homogeneous reaction in fluid are adopted to describe the combustion. The Stefan flow near the particle surface caused by the heterogeneous reactions is also considered. A satisfactory agreement can be found between the present simulation results and the previous experimental and numerical results. Three flame modes of a char particle combustion and the transition mechanisms between them are investigated. Furthermore, the effect of hydrodynamic interaction and the oxygen concentration in O 2 /CO 2 atmosphere on particle combustion behavior are explored in detail. The present work establishes the foundation for the efficient simulations of particle combustion with size change and motion. • IB-LBM is developed for particle combustion with varying thermodynamic and transport properties. • Results are validated by comparing with previous experiments and simulations. • Particle combustion behaviors in O 2 /N 2 and in O 2 /CO 2 atmosphere are compared. [ABSTRACT FROM AUTHOR]

Presents a novel photonic bandgap structure for microwave integrated circuits. Slow-wave factor of a microstrip line; Numerical simulation results; Insertion losses; Bandpass electric filters; Slow wave factors.

Presents a study discussing numerical and experimental corroboration of a finite-difference time-domain (FDTD) thin-slot model which can be used for modeling thin slots near corners of shielding enclosures. What numerical modeling of enclosure designs can aid in; Geometry employed for FDTD modeling; What the results of the study indicated.

Investigates the subcellular modeling of thin slots in the finite difference time-domain (FDTD) method. Comparison of subcellular algorithms for modeling thin slots with the FDTD method; Stability of algorithms; Results for scattering from a finite-length slot.

[Display omitted] • The GO/4A composite is successfully prepared via a one-step hydrothermal method. • The kinetics of the adsorption process could be fitted validly by the Langmuir isotherm and Pseudo-second order model. • GO/4A composite possesses 291% adsorption capacity compared with pure 4A molecular sieve. • GO/4A composite demonstrates an efficient removal and separation performances during adsorption. Dye pollutants in various water resources have brought about severe damages to individuals' health. To attenuate the adverse effects on human beings, we design a novel composite based on graphene oxide and molecular sieve 4A (GO/4A) towards efficient removal of Rhodamine B (RB) in aqueous solutions. The adsorption properties were tested via adjusting experimental conditions, and the adsorption capacity of GO/4A-3 for RB reached as high as 62.81 mg·g−1 when pH equaled 3. Compared with acid-modified 4A molecular sieve, the removal performance of RB was improved by 291%, attributed to the electrostatic interaction between GO and RB dye molecules. The successful combination of GO and 4A molecular sieve also effectively improved the poor separation performance of GO itself. Adsorption isotherm and kinetic studies demonstrated that the adsorption of RB on GO/4A-3 composite followed the Langmuir isotherm (R2 = 0.996) and pseudo-second-order kinetic model (R2 = 1). The thermodynamics of adsorption showed that the RB was spontaneously, endothermically, and entropy-increasing adsorbed onto 4A molecular sieve and GO/4A composites. This study provided a facile and efficient way to process the difficult-to-decompose dye wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • The electrospun PAN/GO/PI nanofibrous membranes demonstrate high filtration efficiency and low pressure drop. • The PAN/GO/PI nanofibrous membranes possess stable filtration ability under high temperatures. • The PAN/GO/PI nanofibrous membranes are promising for widespread application in air filtration. Particulate matter (PM) pollution can severely affect human health. Currently, the most dangerous air pollutant is PM 2.5 which refers to particles with a diameter less than 2.5 μm. In order to mitigate the detrimental effects of PM 2.5 , there is an urgent demand for an air filter with improved performance. In this study, graphene oxide (GO), polyacrylonitrile (PAN), and polyimide (PI) are combined to prepare PAN/GO/PI nanofibrous membranes for efficient air filtration via electrospinning. The as-prepared PAN/GO/PI-6 nanofibrous membranes demonstrate high filtration efficiency (99.5%), low pressure drop (92 Pa), remarkable thermal stability (300 °C), and excellent mechanical strength. Built upon the above merits, this kind of nanofibrous membrane can account for widespread utilization in both industrial applications and civil health warrants. [ABSTRACT FROM AUTHOR]