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Microplastics (MPs) pollution of environments due to human activities is a global concern. In the present study, we examined the occurrence of MPs in coastal hill soils (burned and non-burned) collected from the Rohingya Refugee camps in Cox's Bazar, Bangladesh. The total number of MPs per kg of burned soil (402–403 items/kg) sample was significantly higher than that in non-burned soil (210 items/kg) sample. Fibers (24–57%) dominated in all the samples, followed by fragments (18–51%), sheet (12–29%), and microbeads (12–13%). The most common color of MPs was blue (16–68%), followed by red (14–25%), transparent (14–24%) and brown (14–22%). Among the size groups, MPs of 0.5-<1.0 mm (34–44%) dominated in all the samples, followed by 1.0–5.0 mm (27–45%) and <0.5 mm (14–29%). Attenuated Total Reflectance Fourier Transform Infrared spectroscopy analysis confirmed the most abundant polymer type in burned soil was polystyrene (28%) followed by polypropylene (23%), polyethylene (21%), polyamide (15%), ethylene-vinyl acetate (8%), and polyvinyl chloride (3%). The study confirms the presence of high MPs loads in burned soil, with high potential of trophic transfer to plants and washed out to aquatic environment and will appear as base line information for further assessment of MPs effects on biota. [ABSTRACT FROM AUTHOR]

Numerical results of plasma supported deflagration to detonation transition have been presented. The mathematical model includes Reynolds averaged Navier-Stokes equations for the compressible medium, enthalpy equation, the standard k- ω turbulence model, transport equations for the progress variable and flame wrinkling factor. Non-equilibrium plasma was modeled as a source of radicals. Initial concentrations of radicals were taken from the detailed plasma simulation using a three-temperature plasma model. To model equilibrium plasma we used a Joule heating source with the conductivity depending on the energy deposition time. Simulations showed that the injection of radicals was more efficient than a thermal effect of plasma in the deflagration to detonation transition time and distance. We observed changes in the detonation cell size and improvement of the detonation structure stability with the plasma addition. Because the oxygen atoms injection primarily controls the phenomenon, the detonation cell size depends on the oxygen atoms concentration and on the orientation of the plasma energy spot with respect to the detonation wave. [ABSTRACT FROM AUTHOR]