Vertical Flux of Microplastics in the Deep Subtropical Pacific Ocean: Moored Sediment-Trap Observations within the Kuroshio Extension Recirculation Gyre.

The Kuroshio Extension recirculation gyre in the western North Pacific is an accumulation site of plastic litter transported by the Kuroshio Current. A sediment trap was moored at a depth of 4900 m at Station KEO within the Kuroshio Extension recirculation gyre, and the vertical flux of microplastics in sinking particles of size <1 mm was observed. Forty-one sediment-trap samples collected from July 1, 2014, to October 2, 2016, were analyzed with a micro-Fourier transform infrared spectrometer and microplastics were detected in all samples. Seventeen polymer types were identified, and 90% of the microplastics were less than 100 µm in size. Microplastic sinking was driven by the action of the biological pump, which was in turn driven by seasonal variations in solar radiation and increased surface primary production typical of the spring season. Microplastic mass flux varied from 4.5 × 10-3 to 0.38 mg m-2 day-1 during the sampling period, with a mean and standard deviation of 0.054 ± 0.075 mg m-2 day-1. Extrapolating the annual microplastic mass flux at Station KEO to the entire Kuroshio Extension recirculation gyre, it is estimated that 0.028 million metric tons of microplastics are transported annually to 4900 m depth in this area.

Computational fluid dynamics dataset of secondary air modification in a circulating fluidized bed boiler.

Computer simulation has been proven to provide a good understanding of engineering phenomenon. This work presents numerical simulation results on secondary air jet penetration into a dense phase of a three-dimensional fluidized bed at a commercial scale. Initial model as a reference and four modified models which are called as case A, B, C, and D were created by modifying the angle of secondary air. Evaluation of combustion process is based on mass fraction distribution of H2O and CO2 at center line of the furnace. Generally, modified geometry improves the performance of furnace compared to reference. We also present data of total energy and temperature to get a comprehensive insight of the furnace performance. The simulation results can be used as a consideration to improve the efficiency of steam power plants by adjusting the direction of secondary air flow.